Synthesis of diazaphosphacycles

ABSTRACT

A diazaphosphacycle may be synthesized by reacting a phosphine with a diimine and optionally one or more equivalents of an acid halide, a sulfonyl halide, a phosphoryl halide, or an acid anhydride in the substantial absence of O 2  to form the diazaphosphacycle. The phosphine has the formula R 1 —PH 2  where R 1  is a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted ferrocenyl group.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a divisional of and claims priority to U.S. Ser. No.09/911,367, filed Jul. 23, 2001, now U.S. Pat. No. 7,071,357 the entiredisclosure of which is hereby incorporated by reference in its entiretyand for all purposes as if fully set forth herein.

GOVERNMENT RIGHTS

This invention was made with United States government support awarded bythe following agency: DOE DE-FG02-99ER14949. The United States hascertain rights in this invention.

FIELD OF THE INVENTION

The invention relates generally to diazaphosphacycles and to methods forsynthesizing them. The invention also relates to metal complexes thatmay be formed from the novel diazaphosphacycles and to their use ascatalysts.

BACKGROUND OF THE INVENTION

Phosphines are used as ligands in a large number of known transitionmetal complexes, and phosphine ligands are included in many transitionmetal complexes used as catalysts. One of the reasons is that phosphinesare known to be one of the best ligands for stabilizing transitionmetals. Phosphine ligands are often included in transition metalcomplexes used to catalyze hydroformylation reactions where hydrogen, analkene, and carbon monoxide are converted to the corresponding aldehyde.

Phosphines are also included as ligands in various transition metalcomplexes used to catalyze hydrogenation reactions. In many of thesereactions, inexpensive phosphines such as triphenylphosphine performsuitably. However, phosphines have also found a niche in morespecialized areas such asymmetric hydrogenation and other catalytictransformations. The use of a chiral phosphine allows enantioselectivityin the catalytic reaction, and often high enantiomeric excesses may beachieved when a chiral phosphine is used as a ligand. The use of anenantioselective catalyst allows a desired enantiomer to be producedreducing undesired products while simultaneously reducing separationcosts associated with the separation of enantiomers. Enantioselectivehydrogenation catalysts may be as fast and selective as some of the bestknown enzymes, and such catalysts can result in greater than 99.9%production of one enantiomer.

Asymmetric hydrogenation is used to make commercially important productsincluding biologically active compounds such as pesticides andpharmaceuticals. Asymmetric hydrogenation is being used more frequentlyin the pharmaceutical industry where expensive intermediate compoundsare too valuable to waste. One of the first reactions employing aphosphine-containing catalyst in the pharmaceutical industry was theselective production of L-DOPA rather than R-DOPA.

As noted above, chiral phosphine ligands are central to manydevelopments in transition metal-catalyzed enantioselectivetransformations. R. Noyori, Asymmetric Catalysis; John Wiley: New York,1994. Recent demonstrations of high enantioselectivity for a wide rangeof hydrogenation reactions with Rh complexes of the DuPHOS, PennPHOS,RoPHOS, BASPHOS, CnrPHOS, and related ligands highlight the unusualefficacy of rigid phosphacycles. M. J. Burk, J. Am. Chem. Soc. 1991,113, 8518-8519; M. J. Burk, Chemtracts-Organic Chemistry 1998,11,787-802; M. J. Burk, A. Pizzano, J. A. Martin, L. M. Liable-Sands, A. L.Rheingold, Organometallics 2000, 19, 250-260; M. J. Burk, F. Bienewald,S. Challenger, A. Derrick, J. A. Ramsden, J. Org. Chem. 1999, 64,3290-3298; Z. Zhang, G. Zhu, Q. Jiang, D. Xiao, X. Zhang, J. Org. Chem.1999, 64, 1774-1775; Q. Jiang, Y. Jiang, D. Xiao, P. Cao, X. Zhang,Angew. Chem. 1998, 110, 1100-1103; Angew. Chem., Int. Ed. Engl 1998, 37,1100-1103; G. Zhu, P. Cao, Q. Jiang, X. Zhang, J. Am. Chem. Soc. 1997,119, 1799-1800; Z. Chen, Q. Jiang, G. Zhu, D. Xiao, P. Cao, C. Guo, X.Zhang, J. Org. Chem. 1997, 62, 4521-4523; J. Holz, M. Quirmbach, U.Schmidt, D. Heller, R. Stürmer, A. Börner, J. Org. Chem. 1998, 63,8031-8034; W. Li, Z. Zhang, D. Xiao, X. Zhang, J. Org. Chem. 2000, 65,3489-3496; W. Li, Z. Zhang, D. Xiao, X. Zhang, Tetrahedron Lett. 1999,40, 6701-6704; Y.-Y. Yan, T. V. RajanBabu, J. Org. Chem. 2000, 65,900-906; J. Holz, D. Heller, R. Stürmer, A. Börner, Tetrahedron Lett.1999, 40, 7059-7062; A. Marinetti, S. Jus, J.-P. Genêt, TetrahedronLett. 1999, 40, 8365-8368; A. Marinetti, S. Jus, J.-P. Genêt, L. Ricard,Tetrahedron 2000, 56, 95-100; A. Marinetti, S. Jus, J.-P. Genêt,Tetrahedron Lett. 1999, 40, 8365-8368; A. Marinetti, S. Jus, J.-P.Genêt, L. Ricard, Tetrahedron 2000, 56, 95-100.

Although significant efforts have been made to produce transition metalcomplexes for effecting enantioselective catalytic transformations, onepersisting problem associated with chiral phosphine ligands is that theyare difficult and expensive to produce, often requiring multi-stepsyntheses. Both the electron density of the phosphorus atom inphosphines and the size of the phosphine ligand as expressed by coneangles are known to impact the reactivity of metal complexes preparedfrom them. Therefore, the ability to modify chiral phosphines anddetermine structure property relationships are important factors inunderstanding and optimizing catalytic activity. However, the difficultyassociated with synthesizing chiral phosphines has prevented thesynthesis of libraries of such compounds for use in analyzing structureproperty relationships.

One specific group of phosphines, 3,4-diazaphospholanes, arefive-membered rings containing two nitrogen atoms, two carbon atoms, anda phosphorus atom as ring members. In 3,4-diazaphospholanes, each of thetwo carbon atom ring members is bonded to one of the ring nitrogen atomsand the ring phosphorus atom. Very few 3,4-diazaphospholanes have thusfar been reported.

Märkl et al. have prepared diazaphospholanes by reacting hydrazines withphosphorus compounds having the formula RP(CH₂OH)₂. This syntheticmethodology is limited and does not provide any simple route tocompounds having groups other than H bonded to the diazaphospholane ringcarbon atoms. G. Märkl, G. Y. Jin, Tetrahedron Lett. 1980, 21,3467-3470; and G. Märkl, G. Y. Jin, Tetrahedron Lett. 1981, 22, 229-232.Arbuzov et al. have utilized the same type of methodology to prepareother diazaphosphacycles from RP(CH₂OH)₂. B. A. Arbuzov, O. A. Erastov,G. N. Nikonov, R. P. Arshinova, I. P. Romanova, R A. Kadyrov, IzvestiaAkad, Nauk S S S R, Seriya Khimicheskaya, 1993, 8, 1846-1850.

A need remains for chiral phosphines and methods for making them. A needalso remains for transition metal complexes that include chiralphosphines and for transition metal complexes for catalyzing importantreactions. A need further remains for libraries of chiral phosphines andtransition metal complexes.

SUMMARY OF THE INVENTION

The present invention provides diazaphosphacycles and methods forsynthesizing them. The invention also provides transition metalcomplexes that include diazaphosphacycles and methods for using them incatalytic transformations.

A method of synthesizing a diazaphosphacycle is provided which includesreacting a phosphine with a diimine and optionally one or moreequivalents of an acid halide, a sulfonyl halide, a phosphoryl halide,or an acid anhydride in the substantial absence of O₂ to form thediazaphosphacycle. The phosphine has the formula I

where R¹ is selected from the group consisting of substituted andunsubstituted aryl groups, substituted and unsubstituted alkyl groups,substituted and unsubstituted alkenyl groups, substituted andunsubstituted cycloalkyl groups, and substituted and unsubstitutedferrocenyl groups.

Methods for synthesizing diazaphosphacycles are also provided in whichthe diimine has the formula II and the diazaphosphacycle formed has theformula III

where:

-   R² and R³ are independently selected from the group consisting of    substituted and unsubstituted aryl groups, substituted and    unsubstituted alkyl groups, substituted and unsubstituted cycloalkyl    groups, substituted and unsubstituted heterocyclyl groups, and    substituted and unsubstituted ferrocenyl groups;-   R⁴ is selected from the group consisting of —H, substituted and    unsubstituted alkyl groups, substituted and unsubstituted cycloalkyl    groups, substituted and unsubstituted aryl groups, trialkylsilyl    groups, triarylsilyl groups, alkyldiarylsilyl groups,    dialkylarylsilyl groups, —C(═O)—R⁶ groups, —S(═O)₂—R⁶ groups,    —P(═O)R⁶R⁷ groups, and —C(═NR⁶)—R⁷ groups;-   R⁵ is selected from the group consisting of —H, substituted and    unsubstituted alkyl groups, substituted and unsubstituted cycloalkyl    groups, substituted and unsubstituted aryl groups, trialkylsilyl    groups, triarylsilyl groups, alkyldiarylsilyl groups,    dialkylarylsilyl groups, —C(═O)—R⁷ groups, —S(═O)₂—R⁶ groups,    —P(═O)R⁶R⁷ groups, and —C(═NR⁶)—R⁷ groups;-   R⁶ is selected from the group consisting of substituted and    unsubstituted alkyl groups, substituted and unsubstituted alkenyl    groups, substituted and unsubstituted cycloalkyl groups, substituted    and unsubstituted aryl groups, —OH groups, substituted and    unsubstituted alkoxy groups, substituted and unsubstituted aryloxy    groups, —NH(alkyl) groups, —NH(aryl) groups, —N(aryl)₂ groups,    —N(alkyl)₂ groups, —N(alkyl)(aryl) groups, —S-alkyl groups, and    S-aryl groups;-   R⁷ is selected from the group consisting of substituted and    unsubstituted alkyl groups, substituted and unsubstituted alkenyl    groups, substituted and unsubstituted cycloalkyl groups, substituted    and unsubstituted aryl groups, —OH groups, substituted and    unsubstituted alkoxy groups, substituted and unsubstituted aryloxy    groups, —NH(alkyl) groups, —NH(aryl) groups, —N(aryl)₂ groups,    —N(alkyl)₂ groups, —N(alkyl)(aryl) groups, —S-alkyl groups, and    S-aryl groups;-   R⁶ and R⁷ may be part of the same alkyl group, alkenyl group, or    aryl group such that R⁴ and R⁵ together with the two nitrogen atoms    of the diazaphosphacycle form a ring; and-   Y is a linking group selected from the group consisting of    substituted and unsubstituted cycloalkyl groups, substituted and    unsubstituted aryl groups, substituted and unsubstituted alkenyl    groups, silyl groups, substituted alkyl groups, and groups having    the formula —(CH₂)_(n)— wherein n is selected from the group    consisting of 0, 1, 2, and 3.

Some methods are provided in which n is 0. Other methods are provided inwhich R² and R³ are identical, but are not part of the same group. Stillother methods are provided in which Y is a cycloalkyl group, wherein oneof the N atoms of the diimine is bonded to a first ring member C atom ofthe cycloalkyl group and the other N atom of the diimine is bonded to asecond ring member C atom that is bonded to the first ring member Catom. Yet other methods are provided in which Y has the formula

and the benzene ring of Y may be additionally substituted.

Methods are also provided in which the diazaphosphacycle is selectedfrom compounds having the formula IIIA or IIIB or mixtures thereof

Still other methods are provided in which the diazaphosphacycle has theformula IIIC

Still other methods for synthesizing a diazaphosphacycle are provided inwhich the phosphine and the diimine are reacted in the presence of anacid such as hydrochloric acid or hydrobromic acid.

In still other provided methods for synthesizing a diazaphosphacycle,the phosphine and the diimine are reacted in the presence of the acidhalide, the sulfonyl halide, the phosphoryl halide, or the acidanhydride, and at least one of R⁴ and R⁵ is not H. In still other suchmethods R⁴ is a —C(═O)—R⁶ group and R⁵ is a —C(═O)—R⁷ group. In stillother methods in which the phosphine and the diimine are reacted in thepresence of an acid halide, the acid halide is phthaloyl dichloride orphthaloyl dibromide.

Other methods for synthesizing a diazaphosphacycle are provided in whichR¹ includes one or more —PH₂ group such that the phosphine is apolyphosphine. In still other such methods, the polyphosphine isselected from 1,2-diphosphinoethane, 1,2-diphosphinoethylene,1,3-diphosphinopropane, substituted or unsubstituted1,2-diphosphinobenzene groups, substituted or unsubstituted1,8-diphosphinoanthracene groups, substituted or unsubstituted1,8-diphosphino-9,10-dihydroanthracene groups, substituted orunsubstituted 1,8-diphosphinoxanthene groups, or1,1′-diphosphinoferrocene groups.

Still other method for synthesizing diazaphosphacycles are provided inwhich the phosphine, the diimine, and optionally the acid halide arereacted in a substantially deoxygenated solvent such as ether, analcohol, water, dichloroethane, or combinations of these.

Still further methods for synthesizing diazaphosphacycles are provided.These methods further include reacting an acid halide, an acidanhydride, a phosphoryl halide, or a sulfonyl halide with thediazaphosphacycle to produce a second diazaphosphacycle where R⁴ and R⁵are both —H in the diazaphosphacycle and at least one of R⁴ and R⁵ isnot —H in the second diazaphosphacycle.

In yet another provided method, the method is used to generate a libraryof different diazaphosphacycles such as by using a combinatorial method.

Another method for synthesizing a diazaphosphacycle is provided. Themethod includes reacting a diimine with an acid halide, a diaciddihalide, a sulfonyl halide, a disulfonyl dihalide, a phosphoryl halide,or a diphosphoryl dihalide to form a dihalo intermediate compound. Themethod further includes reacting the dihalo intermediate compound with aphosphine of formula R¹—PH₂ in the substantial absence of O₂ to form thediazaphosphacycle. In the method, R¹ is selected from substituted orunsubstituted aryl groups, substituted or unsubstituted alkyl groups,substituted or unsubstituted alkenyl groups, substituted orunsubstituted cycloalkyl groups, or substituted or unsubstitutedferrocenyl groups; and the diimine has the formula IV

where R⁸ and R⁹ are independently selected from substituted orunsubstituted aryl groups, substituted or unsubstituted alkyl groups,substituted or unsubstituted cycloalkyl groups, substituted orunsubstituted heterocyclyl groups, or substituted or unsubstitutedferrocenyl groups.

Still other such methods are provided in which the diimine is reactedwith a diacyl dihalide, and the diacyl dihalide has the formula V or theformula VI and the diazaphosphacycle has the formula VII or the formulaVIII

where:

-   R¹⁰, R¹¹, R¹², and R¹³ are independently selected from —H,    substituted or unsubstituted alkyl groups, substituted or    unsubstituted cycloalkyl groups, or substituted or unsubstituted    aryl groups;-   R¹⁰ and R¹¹ may join together to form a substituted or unsubstituted    aryl group or a substituted or unsubstituted cycloalkenyl group;-   R¹² and R¹³ may join together to form a substituted or unsubstituted    cycloalkenyl group or a substituted or unsubstituted cycloalkyl    group; and-   X and Z are independently selected from the group consisting of —Cl    and —Br.

Other methods are provided in which R⁸ and R⁹ are identical but are notpart of the same group and in which R⁸ and R⁹ are substituted orunsubstituted aryl groups.

Still other methods for synthesizing diazaphosphacycles are provided inwhich the diacyl dihalide is phthaloyl dichloride.

The invention further provides diazaphosphacycles having the formula IIIand salts of the diazaphosphacycles.

In formula III,

-   R¹ is selected from substituted or unsubstituted aryl groups,    substituted or unsubstituted alkyl groups, substituted or    unsubstituted alkenyl groups, substituted or unsubstituted    cycloalkyl groups, or substituted or unsubstituted ferrocenyl    groups;-   R² and R³ are independently selected from substituted or    unsubstituted aryl groups, substituted or unsubstituted alkyl    groups, substituted or unsubstituted cycloalkyl groups, substituted    or unsubstituted heterocyclyl groups, or substituted or    unsubstituted ferrocenyl groups;-   R⁴ is selected from —H, substituted or unsubstituted alkyl groups,    substituted or unsubstituted cycloalkyl groups, substituted or    unsubstituted aryl groups, trialkylsilyl groups, triarylsilyl    groups, alkyldiarylsilyl groups, dialkylarylsilyl groups, —C(═O)—R⁶    groups, —S(═O)₂—R⁶ groups, —P(═O)R⁶R⁷ groups, or —C(═NR⁶)—R⁷ groups;-   R⁵ is selected from —H, substituted or unsubstituted alkyl groups,    substituted or unsubstituted cycloalkyl groups, substituted or    unsubstituted aryl groups, trialkylsilyl groups, triarylsilyl    groups, alkyldiarylsilyl groups, dialkylarylsilyl groups, —C(═O)—R⁷    groups, —S(═O)₂—R⁶ groups, —P(═O)R⁶R⁷ groups, or —C(═NR⁶)—R⁷ groups;-   R⁶ is selected from substituted or unsubstituted alkyl groups,    substituted or unsubstituted alkenyl groups, substituted or    unsubstituted cycloalkyl groups, substituted or unsubstituted aryl    groups, —OH groups, substituted or unsubstituted alkoxy groups,    substituted or unsubstituted aryloxy groups, —NH(alkyl) groups,    —NH(aryl) groups, —N(aryl)₂ groups, —N(alkyl)₂ groups,    —N(alkyl)(aryl) groups, —S-alkyl groups, or S-aryl groups;-   R⁷ is selected from substituted or unsubstituted alkyl groups,    substituted or unsubstituted alkenyl groups, substituted or    unsubstituted cycloalkyl groups, substituted or unsubstituted aryl    groups, —OH groups, substituted or unsubstituted alkoxy groups,    substituted or unsubstituted aryloxy groups, —NH(alkyl) groups,    —NH(aryl) groups, —N(aryl)₂ groups, —N(alkyl)₂ groups,    —N(alkyl)(aryl) groups, —S-alkyl groups, or S-aryl groups;-   R⁶ and R⁷ may be part of the same alkyl group, alkenyl group, or    aryl group such that R⁴ and R⁵ together with the two nitrogen atoms    of the diazaphosphacycle form a ring; and-   Y is a linking group selected from the group consisting of    substituted and unsubstituted cycloalkyl groups, substituted and    unsubstituted aryl groups, substituted and unsubstituted alkenyl    groups, silyl groups, substituted alkyl groups, and groups having    the formula —(CH₂)_(n)— where n is selected from 0, 1, 2, or 3.

Still further diazaphosphacycles are provided in which n is 0. Yet otherdiazaphosphacycles are provided in which R⁴ and R⁵ are both —H. Stillother diazaphosphacycles are provided in which R⁴ is a —C(═O)—R⁶ groupand R⁵ is a —C(═O)—R⁷ group.

Still further diazaphosphacycles are provided which have the formula IXwhere R¹, R², and R³ have any of the values set forth above and in whichthe benzene ring of formula IX may be substituted or unsubstituted

Still further diazaphosphacycles are provided that have the formulaIIIA, IIIB, or IIIC as set forth above.

Still further diazaphosphacycles are provided in which thediazaphosphacycle is present as a mixture of enantiomers.

Still further diazaphosphacycles are provided in which Y is a cycloalkylgroup. In some diazaphosphacycles where Y is a cycloalkyl group, one ofthe N atoms is bonded to a first ring member C atom of the cycloalkylgroup and the other N atom is bonded to a second ring member C atom thatis bonded to the first ring member C atom.

Still other diazaphosphacycles are provided in which Y has the formula

and the benzene ring of Y may be additionally substituted.

The invention further provides diazaphosphacycles having the formula X

where L is a linking group selected from substituted or unsubstitutedalkyl groups, substituted or unsubstituted alkenyl groups, substitutedor unsubstituted aryl groups, or substituted and unsubstitutedferrocenyl groups, and the other variables have the values set forthwith respect to the diazaphosphacycles of formula III set forth above.Still other such diazaphosphacycles are provided in which L is selectedfrom ethane, ethylene, propane, benzene, anthracene,9,10-dihydroanthracene, xanthene, or ferrocene. Transition metalcomplexes including these diazaphosphacycles are also provided in whichat least one of the phosphorus atoms of the diazaphosphacycle is bondedto the transition metal. In other such transition metal complexes two ofthe phosphorus atoms of the diazaphosphacycle are bonded to thetransition metal.

The invention further provides combinatorial libraries that include acollection of different diazaphosphacycles of the present invention.

The invention further provides transition metal complexes that include adiazaphosphacycle according to the invention and a transition metalwhere the phosphorus atom of the diazaphosphacycle is bonded to thetransition metal. Transition metal complexes are further provided inwhich the transition metal is selected from of Rh, Ru, Pd, Pt, Ir, Ni,Co, or Fe. Still other transition metal complexes are provided in whichthe transition metal complex has catalytic activity. A method forcatalyzing a chemical reaction using a transition metal complex of thepresent invention as a catalyst is further provided. Furthermore, theinvention provides libraries of transition metal complexes that includea collection of different transition metal complexes that include thediazaphosphacycles of the present invention.

Methods for synthesizing diazaphosphacycle transition metal complexesare further provided. The methods include reacting a diazaphosphacycleof the present invention with a starting transition metal complex toproduce the diazaphosphacycle transition metal complex. The startingtransition metal complex includes at least one ligand that is replacedby the diazaphosphacycle.

Other methods for synthesizing a diazaphosphacycle transition metalcomplex are provided in which the ligand replaced by thediazaphosphacycle is selected from phosphines; amines; diamines; CO; Cl;Br; nitrites; 1,5-cyclooctadiene, norbornadiene, and other dienes;alkenes; arenes; ketones; alcohols; ethers; thiols; or sulfoxides.

Further objects, features and advantages of the invention will beapparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an X-ray crystal structure ORTEP diagram of rac-6e with thedisplacement ellipsoids drawn at the 50% probability level.

FIG. 2 is an X-ray crystal structure of rac-8. The ORTEP diagram isdrawn with 30% probability ellipsoids. Solvent molecules and hydrogenshave been removed for clarity.

FIG. 3 is a diagram showing a few of the catalytic reactions that metalcomplexes with phosphorus ligands catalyze.

FIG. 4 is a ³¹P NMR spectrum (¹H coupled) of compound 1a with a rac:mesoratio of about 30:1.

FIG. 5 is a ³¹P NMR spectrum (¹H coupled) of meso-3.

FIG. 6 is a ³¹P NMR spectrum (¹H coupled) of compound 7.

FIG. 7 is a ¹H NMR spectrum of a Rh(NBD)(Cl) complex with compoundrac-6b.

FIG. 8 is a GC spectrum for the hydrogenation product of thehydrogenation of methylacetamidoacrylate using a chiral column with aracemic mixture of the catalyst with a Rh diazaphosphacycle complex.

FIG. 9 is a ¹H NMR spectrum of a Rh(NBD)(Cl) complex with compoundrac-6a.

FIG. 10 is a ³¹P NMR spectrum (¹H coupled) of a Rh(NBD)(Cl) complex withcompound rac-6a.

FIG. 11 is a ¹H NMR spectrum of[{1,2-bis(diazaphospholanes)benzene}RhCl]₂ where the1,2-bis(diazaphospholane)benzene is compound 8.

FIG. 12 is a ³¹P NMR spectrum (¹H coupled) of[{1,2-bis(diazaphospholanes)benzene}RhCl]₂ where the1,2-bis(diazaphospholane)benzene is compound 8.

FIG. 13 is a stacked NMR spectrum comparing the ³¹P NMR spectrum of[{1,2-bis(diazaphospholanes)benzene}RhCl]₂ (top) with that of{Rhodium[1,2-bis(diazaphospholanes)benzene](COD)}BF₄ (bottom) where the1,2-bis(diazaphospholane)benzene is compound 8.

FIG. 14 is an X-ray crystal structure ORTEP diagram of[{1,2-bis(diazaphospholanes)benzene}RhCl]₂ where the1,2-bis(diazaphospholane)benzene is compound 8.

FIG. 15 is an X-ray crystal structure ORTEP diagram of a Rh(NBD)(Cl)complex with compound rac-6a.

FIG. 16 is an X-ray crystal structure ORTEP diagram of a methylenechloride solvated Rh(NBD(Cl) complex with a diazaphospholane (6).

DETAILED DESCRIPTION OF THE INVENTION

Generally, the invention provides diazaphosphacycles such as, but notlimited to, 3,4-diazaphospholanes, and methods for preparing them. Theinvention also generally provides transition metal complexes and methodsfor preparing them from diazaphosphacycles. The metal complexes havecatalytic activity and are suitable for use in a wide variety ofcatalytic transformations such, as, but not limited to, hydrogenationand hydroformylation reactions. The invention also provides libraries ofdiazaphosphacycles and transition metal complexes includingdiazaphosphacycles.

Variables used in the chemical formulas are understood to be usedconsistently throughout. For example, R¹ is used to refer to the samegroups unless otherwise specifically noted.

The phrase “diazaphosphacycles” refers to a cyclic compound thatincludes one phosphorus atom and two nitrogen atoms as ring members. Thephrase “diazaphospholane” refers to a five membered ring that includesone phosphorus atom and two nitrogen atom ring members. Adiazaphospholane is a type of a diazaphosphacycle.

A reaction or method run in the “substantial absence of oxygen” meansthat the reaction is carried out using standard methodology known tothose skilled in the art of working with air-sensitive compounds. Thisdoes not require the complete absence of O₂ only the absence of enoughoxygen so that oxygen does not interfere with the desired reaction.Common procedures for performing a reaction or method in the substantialabsence of oxygen include, but are not limited to the use of Schlenktechniques, the use of glove bags or glove boxes, and the use ofsolvents from which most, if not all, of the oxygen has been removedusing standard techniques such as by bubbling an inert gas through thesolvent or by freeze-pump-thaw techniques known to those skilled in theart. A reaction performed in the substantial absence of oxygen isgenerally conducted under an inert atmosphere such as under a N₂ orargon atmosphere.

Generally, a reference to a certain element such as hydrogen or H ismeant to include all isotopes of that element. For example, a compoundhaving the structure R—PH₂ is defined to include those compounds whereone or both of the H atoms bonded to the P atom is replaced by adeuterium atom, a tritium atom, or both. An exception to the generaldefinition that reference to a certain element is meant to include allisotopes of that element is when the element is referred to with respectto NMR spectroscopy or a deuterated solvent used in conjunction with NMRspectroscopy.

A wavy line drawn through a line in a structural formula indicates pointof attachment of a group.

A wavy line drawn between an atom and a group in a structural formulaindicates that a bond exists between the atom and the group, but thatthe position of the group is not specified. For example a wavy bondbetween an alkene carbon atom and a group may be used to represent cisand trans isomers, and a wavy bond from an alkyl carbon to a groupindicates that no stereochemistry is assigned and the wavy bond may thusbe used to represent both S and R configurations at the alkyl carbon.

The acronym “COD” refers to 1,5-cyclooctadiene.

The acronym “NBD” refers to 2,5-norbornadiene also known asbicyclo[2.2.1]hepta-2,5-diene and norbornadiene.

The phrase “unsubstituted alkyl” refers to alkyl groups that do notcontain heteroatoms. Thus the phrase includes straight chain alkylgroups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, dodecyl and the like. The phrase alsoincludes branched chain isomers of straight chain alkyl groups,including but not limited to, the following which are provided by way ofexample: —CH(CH₃)₂, —CH(CH₃)(CH₂CH₃), —CH(CH₂CH₃)₂, —C(CH₃)₃,—C(CH₂CH₃)₃, —CH₂CH(CH₃)₂, —CH₂CH(CH₃)(CH₂CH₃), —CH₂CH(CH₂CH₃)₂,—CH₂C(CH₃)₃, —CH₂C(CH₂CH₃)₃, —CH(CH₃)CH(CH₃)(CH₂CH₃), —CH₂CH₂CH(CH₃)₂,—CH₂CH₂CH(CH₃)(CH₂CH₃), —CH₂CH₂CH(CH₂CH₃)₂, —CH₂CH₂C(CH₃)₃,—CH₂CH₂C(CH₂CH₃)₃, —CH(CH₃)CH₂CH(CH₃)₂, —CH(CH₃)CH(CH₃)CH(CH₃)₂,—CH(CH₂CH₃)CH(CH₃)CH(CH₃)(CH₂CH₃), and others. Thus, the phraseunsubstituted alkyl groups includes primary alkyl groups, secondaryalkyl groups, and tertiary alkyl groups. Preferred unsubstituted alkylgroups include straight and branched chain alkyl groups having 1 to 20carbon atoms. More preferred such unsubstituted alkyl groups have from 1to 10 carbon atoms while even more preferred such groups have from 1 to6 carbon atoms. Most preferred unsubstituted alkyl groups includestraight and branched chain alkyl groups having from 1 to 3 carbon atomsand include methyl, ethyl, propyl, and —CH(CH₃)₂.

The phrase “substituted alkyl” refers to an unsubstituted alkyl group asdefined above in which one or more bonds to a carbon(s) or hydrogen(s)are replaced by a bond to non-hydrogen and non-carbon atoms such as, butnot limited to, a halogen atom in halides such as F, Cl, Br, and I; anoxygen atom in groups such as hydroxyl groups, alkoxy groups, aryloxygroups, and ester groups; a sulfur atom in groups such as thiol groups,alkyl and aryl sulfide groups, sulfone groups, sulfonyl groups, andsulfoxide groups; a nitrogen atom in groups such as amines, amides,alkylamines, dialkylamines, arylamines, alkylarylamines, diarylamines,N-oxides, imides, and enamines; a silicon atom in groups such astrialkylsilyl groups, dialkylarylsilyl groups, alkyldiarylsilyl groups,and triarylsilyl groups; a phosphorus atom in groups such as phosphines,and phosphoryls; and other heteroatoms in various other groups.Substituted alkyl groups also include groups in which one or more bondsto a carbon(s) or hydrogen(s) atom is replaced by a bond to a heteroatomsuch as oxygen in carbonyl, carboxyl, and ester groups; nitrogen ingroups such as imines, oximes, hydrazones, and nitriles. Substitutedalkyl groups include, among others, alkyl groups in which one or morebonds to a carbon or hydrogen atom is/are replaced by one or more bondsto fluorine atoms. Other alkyl groups include those in which one or morebonds to a carbon or hydrogen atom is replaced by a bond to an oxygenatom such that the substituted alkyl group contains a hydroxyl, alkoxy,aryloxy, or heterocyclyloxy group. Still other substituted alkyl groupsinclude alkyl groups that have an amine group.

The phrase “unsubstituted alkenyl” refers to an “unsubstituted alkyl”group as defined above where at least one single C—C bond of theunsubstituted alkyl group is replaced by a double bond.

The phrase “substituted alkenyl” has the same meaning with respect tounsubstituted aryl groups that substituted alkyl groups has with respectto unsubstituted alkyl groups.

The phrase “unsubstituted cycloalkyl” refers to a cycloalkyl group wherenone of the carbon atoms of the cycloalkyl ring is bonded to an elementother than H except for the carbon atom(s) bonded as the point ofattachment. Examples of unsubstituted cycloalkyl groups includecyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, andcyclooctyl groups. Cyclohexyl and cyclopentyl groups are preferredcycloalkyl groups.

The phrase “substituted cycloalkyl” has the same meaning with respect tounsubstituted cycloalkyl groups that substituted alkyl groups have withrespect to unsubstituted alkyl groups. However, a substituted cycloalkylgroup also includes cycloalkyl groups in which one or more ring carbonatoms of the cycloalkyl group is bonded to a substituted and/orunsubstituted alkyl group. Thus, the phrase “substituted cycloalkyl”includes, but is not limited to methylcyclohexyl, and chlorocyclopentylgroups among others.

The phrase “unsubstituted aryl” refers to aryl groups that are notsubstituted. Thus the phrase includes, but is not limited to, groupssuch as phenyl, biphenyl, anthracenyl, naphthenyl, and xanthenyl by wayof example. Although the phrase “unsubstituted aryl” includes groupscontaining condensed rings such as naphthalene, it does not include arylgroups that have other groups such as alkyl or halo groups bonded to oneof the ring members as aryl groups such as tolyl are substituted arylgroups. A preferred unsubstituted aryl group is phenyl. Unsubstitutedaryl groups may be bonded to one or more atom in the parent structuralformula.

The phrase “substituted aryl group” has the same meaning with respect tounsubstituted aryl groups that substituted alkyl groups have withrespect to unsubstituted alkyl groups. However, a substituted aryl groupalso includes aryl groups in which one or more aromatic carbons of thearyl group is bonded to a substituted and/or unsubstituted alkyl group.Thus, the phrase “substituted aryl” includes, but is not limited totolyl, and hydroxyphenyl among others.

All ranges recited herein include all combinations and subcombinationsincluded within that range's limits. For example, a temperature range offrom about 20° C. to about 65° C. includes ranges of from 20° C. to 60°C., of from 25° C. to 30° C., of from 25° C. to 28° C., and of from 20°C. to 30° C., etc. Furthermore, one skilled in the art will recognizethat any listed range can be easily recognized as sufficientlydescribing and enabling the same range being broken down into at leastequal halves, thirds, quarters, fifths, tenths, etc. As a non-limitingexample, each range discussed herein can be readily broken down into alower third, middle third, and upper third.

An acid chloride refers to a compound having at least one carboxylicacid group where the —OH group of the carboxylic acid moiety is replacedwith a halogen group such as, but not limited to, —Cl or —Br. A diaciddichloride is a type of acid chloride and refers to a compound having atleast two carboxylic acid groups where the —OH groups have been replacedwith halogen groups. Examples of diacid dichlorides include, but are notlimited to, oxalyl chloride, phthaloyl dichloride, and phthaloyldibromide.

A method of synthesizing a diazaphosphacycle includes reacting aphosphine with a diimine and optionally one or more equivalents of anacid halide, a sulfonyl halide, a phosphoryl halide, or an acidanhydride in the substantial absence of O₂ to form thediazaphosphacycle. The phosphine has the formula I

R¹ is selected from substituted or unsubstituted aryl groups,substituted or unsubstituted alkyl groups, substituted or unsubstitutedalkenyl groups, substituted or unsubstituted cycloalkyl groups, orsubstituted or unsubstituted ferrocenyl groups. Preferred R¹ groupsinclude substituted and unsubstituted phenyl groups and substituted andunsubstituted cycloalkyl groups such as, but not limited to substitutedand unsubstituted cyclopentyl groups and cyclohexyl groups. Otherpreferred R¹ groups include one or more —PH₂ group such that thephosphine is a polyphosphine. Employing a polyphosphine in the methodprovides for the production of bidentate ligands. Examples of suitablepolyphosphines for use in the methods of the invention include, but arenot limited to, 1,2-diphosphinoethane, 1,2-diphosphinoethylene,1,3-diphosphinopropane, substituted or unsubstituted1,2-diphosphinobenzene groups, substituted or unsubstituted1,8-diphosphinoanthracene groups, substituted or unsubstituted1,8-diphosphino-9,10-dihydroanthracene groups, substituted orunsubstituted 1,8-diphosphinoxanthene groups, or1,1′-diphosphinoferrocene groups.

The reaction of a diimine with a phosphine of formula I is preferablyconducted in a solvent such as, but not limited to, a substantiallydeoxygenated ether such as diethyl ether or tetrahydrofuran; asubstantially deoxygenated alcohol such as ethanol or methanol;substantially deoxygenated water; or substantially deoxygenateddichloroethane. An acid is preferably present when the diimine reactswith the phosphine of formula I. Examples of suitable acids include, butare not limited to hydrochloric acid and hydrobromic acid.

Although not required, in certain preferred methods according theinvention, the diimine and the phosphine are reacted in the presence ofthe optional acid halide, the sulfonyl halide, the phosphoryl halide, orthe acid anhydride. The presence of one of the optional halides oranhydride provides for carboxylation, phosphorylation, or sulfonylationof one or both of the N atoms in diazaphosphacycle ring. In somepreferred embodiments, the method is conducted in the presence of anacid halide such as, but not limited to acetyl chloride, acetyl bromide,phthaloyl dichloride, or phthaloyl dibromide. In other preferredembodiments, the reaction is conducted in the presence of a diaciddihalide such as phthaloyl dichloride or phthaloyl dibromide. In stillother preferred embodiments, the reaction of the diimine with thephosphine is conducted in the presence of an acid anhydride.

The reaction between the diimine and the phosphine is typicallyconducted at temperatures ranging from less than 0° C. to about 50° C.More preferably, the reaction is conducted at temperatures ranging fromat or about 0° C. to at or about 25° C.

In preferred methods of synthesizing diazaphosphacycles, the diiminereacted with the phosphine of formula I has the formula II. In suchmethods, the diazaphosphacycle formed has the formula III

R² and R³ are independently selected from substituted or unsubstitutedaryl groups, substituted or unsubstituted alkyl groups, substituted orunsubstituted cycloalkyl groups, substituted or unsubstitutedheterocyclyl groups, or substituted or unsubstituted ferrocenyl groups.In some preferred methods and diazaphosphacycles of the invention, R²and R³ are identical, but are not part of the same group. In otherwords, if R² is a phenyl group, then R³ is another phenyl group.Preferred R² and R³ groups include phenyl, 2-furanyl, protectedpyrrolyl, n-propyl, i-propyl, t-butyl, ferrocenyl, o-hydroxyphenyl,o-tolyl, 2-naphthyl, and pentafluorophenyl groups.

R⁴ is selected from —H, substituted or unsubstituted alkyl groups,substituted or unsubstituted cycloalkyl groups, substituted orunsubstituted aryl groups, trialkylsilyl groups, triarylsilyl groups,alkyldiarylsilyl groups, dialkylarylsilyl groups, —C(═O)—R⁶ groups,—S(═O)₂—R⁶ groups, —P(═O)R⁶R⁷ groups, or —C(═NR⁶)—R⁷ groups. PreferredR⁴ groups include —H, and —C(═O)—R⁶ groups.

R⁵ is selected from —H, substituted or unsubstituted alkyl groups,substituted or unsubstituted cycloalkyl groups, substituted orunsubstituted aryl groups, trialkylsilyl groups, triarylsilyl groups,alkyldiarylsilyl groups, dialkylarylsilyl groups, —C(═O)—R⁷ groups,—S(═O)₂—R⁷ groups, —P(═O)R⁶R⁷ groups, or —C(═NR⁶)—R⁷ groups. PreferredR⁵ groups include —H and —C(═O)—R⁷ groups. In some preferred methods anddiazaphosphacycles, R⁴ is a —C(═O)—R⁶ group and R⁵ is a —C(═O)—R⁷ group.

R⁶ is selected from substituted or unsubstituted alkyl groups,substituted or unsubstituted alkenyl groups, substituted orunsubstituted cycloalkyl groups, substituted or unsubstituted arylgroups, —OH groups, substituted or unsubstituted alkoxy groups,substituted or unsubstituted aryloxy groups, —NH(alkyl) groups,—NH(aryl) groups, —N(aryl)₂ groups, —N(alkyl)₂ groups, —N(alkyl)(aryl)groups, —S-alkyl groups, or S-aryl groups. Preferred R⁶ groups includealkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexylgroups and groups where R⁶ and R⁷ join together with the two ringnitrogen atoms of the diazaphosphacycle to form a ring.

R⁷ is selected from substituted or unsubstituted alkyl groups,substituted or unsubstituted alkenyl groups, substituted orunsubstituted cycloalkyl groups, substituted or unsubstituted arylgroups, —OH groups, substituted or unsubstituted alkoxy groups,substituted or unsubstituted aryloxy groups, —NH(alkyl) groups,—NH(aryl) groups, —N(aryl)₂ groups, —N(alkyl)₂ groups, —N(alkyl)(aryl)groups, —S-alkyl groups, or S-aryl groups. Preferred R⁷ groups includealkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexylgroups and groups where, as indicated above, R⁶ and R⁷ join togetherwith the two ring nitrogen atoms of the diazaphosphacycle to form aring.

R⁶ and R⁷ may be part of the same alkyl group, alkenyl group, or arylgroup such that R⁴ and R⁵ together with the two nitrogen atoms of thediazaphosphacycle form a ring. Preferred such compounds include thosewhere the ring formed has 6 ring members.

Y is a linking group selected from substituted or unsubstitutedcycloalkyl groups, substituted or unsubstituted aryl groups, substitutedor unsubstituted alkenyl groups, silyl groups, substituted alkyl groups,or groups having the formula —(CH₂)_(n)— wherein n is selected from thegroup consisting of 0, 1, 2, and 3. In some preferred methods anddiazaphosphacycles, Y is a —(CH₂)_(n)— group where n is 0. In suchcompounds the nitrogen atoms of the diazaphosphacycle are directlybonded to one another and the compound is a 3,4-diazaphospholane.

In other preferred methods and diazaphosphacycles, Y is a cycloalkylgroup and one of the nitrogen atoms of the diimine is bonded to a firstring member carbon atom of the cycloalkyl group and the other nitrogenatom of the diimine is bonded to a second ring member carbon atom.Furthermore, in such preferred compounds, the second ring member carbonatom of the cycloalkyl group is directly bonded to the first ring membercarbon atom of the cycloalkyl group such that the cycloalkyl group is a1,2-disubstituted cycloalkyl group such as a 1,2-disubstitutedcyclohexyl group. Both cis and trans 1,2-disubstituted alkyl groups arepreferred. Other preferred Y groups have the following formula where thebenzene ring of the group may be further substituted:

In other preferred methods and diazaphosphacycles, the diazaphosphacyclehas the formula IIIA, the formula IIIB, or is a mixture ofdiazaphosphacycles of formulas IIIA and IIIB. Such diazaphosphacyclesare generally referred to as rac compounds. In more preferred suchdiazaphosphacycles, Y is a —(CH₂)_(n)— group where n is 0.

In other preferred methods and diazaphosphacycles, the diazaphosphacyclehas the formula IIIC. Such compounds are generally referred to as mesocompounds. In more preferred such compounds, Y is a —(CH₂)_(n)— groupwhere n is 0 so that the ring nitrogen atoms of the diazaphosphacycleare directly bonded to one another.

The methods disclosed herein may be used to produce diazaphosphacycleswhere both R⁴ and R⁵ are —H. Such a method typically involves reactionof the phosphine of formula I with the diimine of formula 11 in theabsence of acid halide, acid anhydride, sulfonyl halide, and/orphosphoryl halide. When such a method is used, the method may includethe later addition of an acid halide, an acid anhydride, a sulfonylhalide, or a phosphoryl halide. Preferably an acid halide or an acidanhydride is used in such a method. The later addition of one of theabove-specified reagents forms a second diazaphosphacycle in which atleast one of R⁴ and R⁵ is not —H. In other preferred such methods,neither R⁴ nor R⁵ is an —H in the second diazaphosphacycle.

The widely different groups that may be used for R¹—R⁶ and Y in themethod of the invention allows a library of different diazaphosphacyclesto be produced from readily available starting materials. Such a librarymay be produced using standard combinatorial methods allowing for theproduction of large numbers of diazaphosphacycles.

A first alternative method of synthesizing a diazaphosphacycle includesreacting a diimine with an acid halide, a diacid dihalide, a sulfonylhalide, a disulfonyl dihalide, a phosphoryl halide, or a diphosphoryldihalide to form a dihalo intermediate compound. The method furtherincludes reacting the dihalo intermediate compound with a phosphine offormula R¹—PH₂ in the substantial absence of O₂ to form thediazaphosphacycle. In the method, R¹ is selected from substituted orunsubstituted aryl groups, substituted or unsubstituted alkyl groups,substituted or unsubstituted alkenyl groups, substituted orunsubstituted cycloalkyl groups, or substituted or unsubstitutedferrocenyl groups; and the diimine has the formula IV

R⁸ and R⁹ are independently selected from substituted or unsubstitutedaryl groups, substituted or unsubstituted alkyl groups, substituted orunsubstituted cycloalkyl groups, substituted or unsubstitutedheterocyclyl groups, or substituted or unsubstituted ferrocenyl groups.Any of the reaction conditions suitable for the previously describedmethod may be used in conjunction with this first alternative method. Insome preferred such methods and diazaphosphacycles produced therefrom,R⁸ and R⁹ are identical, but are not part of the same group. In otherwords, if R⁸ is a phenyl group, then R⁹ is another phenyl group.Preferred R⁸ and R⁹ groups include phenyl, 2-furanyl, protectedpyrrolyl, n-propyl, i-propyl, t-butyl, ferrocenyl, o-hydroxyphenyl,o-tolyl, 2-naphthyl, and pentafluorophenyl groups. Substituted andunsubstituted aryl groups are particularly suitable as R⁸ and R⁹ groups.

Still other such methods are provided in which the diimine is reactedwith a diacyl dihalide, and the diacyl dihalide has the formula V or theformula VI and the diazaphosphacycle has the formula VII or the formulaVIII

R¹⁰, R¹¹, R¹², and R¹³ are independently selected from —H, substitutedor unsubstituted alkyl groups, substituted or unsubstituted cycloalkylgroups, or substituted or unsubstituted aryl groups. R¹⁰ and R¹¹ mayfurther join together to form a substituted or unsubstituted aryl groupor a substituted or unsubstituted cycloalkenyl group. Similarly, R¹² andR¹³ may join together to form a substituted or unsubstitutedcycloalkenyl group or a substituted or unsubstituted cycloalkyl group.

X and Z are independently selected from —Cl or —Br.

In particularly preferred methods for synthesizing diazaphosphacyclesaccording to the alternative method, phthaloyl dichloride is the diacyldihalide of formula V.

Preferred diazaphosphacycles include any of the compounds having theformulas III, IIIA, IIIB, IIIC, VII, or VIII produced by any of themethods of the present invention. Preferred diazaphosphacycles of theinvention further include compounds of the formula IX

where R¹, R², and R³ have any of the values set forth above with respectto formula III.

Preferred diazaphosphacycles of formula III include those having theformula X

In compounds of formula X, L is a linking group selected fromsubstituted or unsubstituted alkyl groups, substituted or unsubstitutedalkenyl groups, substituted or unsubstituted aryl groups or substitutedor unsubstituted ferrocenyl groups. Preferred L groups include ethane,ethylene, propane, benzene, anthracene, 9,10-dihydroanthracene,xanthene, and ferrocene. In more preferred such diazaphosphacycles, Y isa —(CH₂)_(n)— group where n is 0.

Scheme 1 shows how various 3,4-diazaphosphacycles may be synthesizedfrom simple starting materials to provide a large number of chiralphosphine ligands.

As shown in Scheme 1, the reaction of 2 equivalents of an aldehyde suchas aldehydes where R is an alkyl group or aryl group with a diamine suchas hydrazine readily affords the diimines for use in the method forproducing the diazaphosphacycles. An excess of aldehyde may be used toproduce the diimine. The reaction shown in Scheme 1 may be carried outin a rac selective manner. The reaction typically provides high yieldsin excess of 80 percent of the 3,4-diazaphospholanes.

Scheme 2 shows the synthesis of numerous different diazaphosphacyclesfrom simple and readily available diimines and phosphines. The diimineis formed from hydrazine and the appropriate aldehyde. Thus, the diimineis a compound of formula II as described above, where Y is a —(CH₂)_(n)—group where n is 0.

^(a)(i) HCl, RPH₂, (ii) CH₃COCl, RPH₂ (iii) succinyl chloride, PhPH₂(iv) succinyl chloride, RPH₂ (v) HCl, PhPH₂ (vi) phthaloyl chloride,PhPH₂ (vii) HCl, 1,2-(PH₂)₂C₆H₄ (viii) phthaloyl chloride in THF (ix)HCl, PH₂CH₂CH₂PH₂. All the reaction products were worked up with 10%K₂CO₃.

The condensation of azines (R²—CH═N—N═CH—R³), shown generically asformula II, prepared by the reaction of hydrazine with 2 equivalents ofthe corresponding aldehyde, as shown in Scheme 1, and primary phosphinesyields diazaphosphacycles such as compound 1. As set forth in Scheme 2,this procedure surprisingly and unexpectedly provides a variety of3,4-diazaphospholanes in good yields (25-95%) and rac selectivity undermild reaction conditions.

Condensation of an azine and a primary phosphine preferably with 1equivalent of dry HCl as an acid promoter affords simple3,4-diazaphospholanes (1, 7, 9). In preferred embodiments, acidchlorides are employed and function as both promoters andN-functionalization reagents to provideN,N′-dicarboxyl-3,4-diazaphospholanes (2, 3, 4, 6) directly in aone-step synthesis as illustrated in Scheme 2. Reaction of the azinederived from acetyl salicylaldehyde with phenylphosphine yielded 5, aproduct in which one of the salicyl acetyl groups was transferred to thehydrazine moiety. As exemplified by the transformation of compound 7 tocompound 8, 3,4-diazaphospholanes and acid chlorides react cleanly toprovide a wide variety of N,N′-dicarboxyl-3,4-diazaphospholanes. TheN,N′-dicarboxyl-3,4-diazaphospholanes exhibit higher thermal andchemical stability than simple 3,4-diazaphospholanes, although both aresuitable for forming transition metal complexes.

Acid-promoted addition of primary phosphines to diimines are generallyrac selective, but the reaction is sensitive to the selection of the R¹group of the phosphine and to the selection of the R², R³, R⁸, and R⁹groups of the diimine used. For example, where R¹ is phenyl, rac/mesoratios (0.6-30:1) are dependent on the choice of R² and R³ or R⁸ and R⁹.However, when R¹ is a cyclohexyl group, then formation of the racisomers are highly preferred and in some cases are the only isomersobserved. Azines derived from bulky, electron withdrawing substituentssuch as pentafluorophenyl and ferrocenyl generally yield low rac/mesoratios (6e, 2:1; 3, 0.6:1). For most diazaphospholanes, simplerecrystallization provides separation of diastereomers (e.g., rac/mesoratios 30:1 for 1a). The diazaphosphacycles were characterized by X-raycrystallography and ¹H and ³¹P NMR spectroscopy as shown in FIGS. 1, 2,and 4-6.

Resolution of enantiomeric mixtures may be accomplished by variousmethods known to those skilled in the art. Resolution of racemicdiazaphospholanes 1a, 1e, and 9 was accomplished by N-functionalizationwith di-O-methyl-L-tartaric acid dichloride to form bicyclicdiastereomers followed by chromatographic separation on silica gel.

Scheme 3 shows how various functionalized 3,4-diazaphospholanes may beprepared from a diimine such as a diimine of formula II where Y is a—(CH₂)_(n)— group and n is 0.

Scheme 4 shows a synthetic route for obtaining rigid bicyclic3,4-diazaphospholanes from a diimine of formula II where Y is a—(CH₂)_(n)— group and n is 0.

Scheme 5 shows a synthetic method that may be used for preparing adiazaphosphacycle that includes a hydroxyphenyl group.

Scheme 6 shows a synthetic method for preparing a sterically demandingdiazaphosphacycle that includes two ferrocenyl groups. As can be seen inScheme 6, one of the products is thermally unstable and can be degraded.

The diazaphosphacycles of the present invention may be combined with atransition metal to form a transition metal complex. The transitionmetal complexes of the invention include a transition metal and adiazaphosphacycle where at least one phosphorus atom in thediazaphosphacycle is bonded to the transition metal. Preferred metalcomplexes are prepared using 3,4-diazaphospholanes. In preferredtransition metal complexes including a diazaphosphacycle of formula X,two of the phosphorus atoms are bonded to the transition metal.Preferred transition metals in transition metal complexes include Rh,Ru, Pd, Pt, Ir, Ni, Co, and Fe. Other preferred transition metalcomplexes have catalytic activity and can be used to catalyzetransformations such as those carried out with known transition metalcomplexes as understood by those skilled in the art. Just a few of thecatalytic transformations possible with the transition metal complexesof the present invention are shown in FIG. 3.

Because the methods of the present invention may be used to readilysynthesize a plethora of diazaphosphacycles, libraries of thesecompounds and transition metal complexes prepared from them may beformed.

Various methods may be used to prepare transition metal complexes fromthe diazaphosphacycles of the present invention.

Such methods include reacting a diazaphosphacycle with a startingtransition metal complex to produce the diazaphosphacycle transitionmetal complex. In such reactions, the starting transition metal complextypically includes at least one ligand that is replaced by thediazaphosphacycle during the reaction. Examples of ligands includephosphines; amines; diamines; CO; Cl, Br; nitriles such as, but notlimited to acetonitrile and benzonitrile; 1,5-cyclooctadiene,norbornadiene, and other dienes; alkenes; ketones; alcohols; ethers;thiols; and sulfoxides. For example, excess diazaphospholanes 6a and 6breact with ½[{Rh(NBD)Cl}₂] affording adducts with the formula[(6)Rh(NBD)Cl] in quantitative yields. Similarly, reaction of theN,N′-phthaloyl derivative of 9 with [(COD)Pt(CH₃)₂] in solution yields[(9-phthaloyl)Pt(CH₃)₂] in quantitative yield as judged by NMRspectroscopy and X-ray crystallography. X-ray crystallography was usedto generate ORTEP diagrams of various metal complexes as seen in FIGS.14, 15, and 16. ¹H and ³¹P NMR spectra of various metal complexes areshown in FIGS. 7, and 9-13.

Standard reaction conditions known to those skilled in the art may beused to promote formation of the transition metal complex. For example,CO displacement may be promoted through the use of ultravioletirradiation or by reaction with trimethylamine N-oxide as known by thoseskilled in the art.

Scheme 7 shows methods for preparing Rh(norbornadiene) complexes thatinclude one or two diazaphosphacycles of the present invention.

Scheme 8 shows various platinum complexes that have been synthesizedusing various diazaphosphacycles of the present invention

Scheme 9 shows various synthesized rhodium complexes that include thediazaphosphacycles of the present invention.

Scheme 10 shows a number of palladium complexes that have beensynthesized using various diazaphosphacycles of the present invention.

As noted above, there are many different types of reaction catalyzed bytransition metal complexes. Examples of such reactions that may becatalyzed by the transition metal complexes of the present inventioninclude, but are not limited to, alkene, alkyne, ketone, imine, oxime,aldehyde, nitrile, arene, carboxylic acid, ester, acid anhydride, andnitro group hydrogenations; hydrogenolysis reactions of alkyl halides,alkenyl halides, and acyl halides; hydrosilylation of alkenes, alkynes,ketones, and oximes; hydroboration of alkenes, alkynes, ketones, andoximes; hydroamination of alkenes and alkynes; hydroformylation ofalkenes; hydroacylation of alkenes; hydrocarboxylation,hydroesterification, and hydrocarboxamidation of alkenes; carbonylationand double carbonylation of alkyl, aryl, and alkenyl halides;hydrocyanation of alkenes, dienes, and alkynes; alkene metathesis;cycloaddition of alkenes, dienes, and alkynes; cyclopropanation ofalkenes; alkene and alkyne isomerization; Tischenko disproportionationof aldehydes; aziridination of alkenes; cross-coupling reactions;diborylation of alkanes; dehydrogenation of alkanes; allylic alkylation;allylic amination; allylic esterification; and amination andetherification of alkenyl and aryl halides. While each of the catalyticreactions is separately preferred, hydrogenation and hydroformylationreactions are particularly preferred transformations where transitionmetal complexes prepared from the diazaphosphacycles of the presentinvention may be utilized. Especially preferred catalytictransformations include those where enantioselectivity is desired.

As a general rule, 3,4-diazaphospholanes are bulky ligands. For example,the cone angle of 1a (172°) is comparable to that oftricyclohexylphosphine (170°). The bulkiness of the3,4-diazaphosphacycles allows for the formation of transition metalcomplexes with crowded metal centers which may be associated withimproved selectivity and/or activity during catalysis. Accordingly,diazaphosphacycles having cone angles greater than 170° are preferred.

EXAMPLES

General Considerations

Routine NMR characterization experiments, ¹H NMR (300 and 500 MHz), ¹³CNMR (75.462 and 125.7 MHz), ¹⁹F NMR (282 MHz), and ³¹P NMR (121.49 and202.4 MHz) were carried out on a Bruker AC-300 or a Varian 500 NMRspectrometer. ¹H NMR data are reported as follows: chemical shift(multiplicity (b=broad, s=singlet, d=doublet, t=triplet, q=quartet, andm=multiplet), and integration). Chemical shifts for ¹H NMR spectra arereported in ppm downfield from internal tetramethylsilane (TMS, δ scale)using residual protons in the deuterated solvents (C₆D₆, 7.15 ppm;CDCl₃, 7.25 ppm; and CD₂Cl₂, 5.31 ppm) as references. ¹³C and 31P NMRspectra were obtained using ¹H decoupling, and the chemical shifts arereported in ppm vs. Me₄Si(CDCl₃ at 77 ppm and C₆D₆ at 128 ppm) and 85%H₃PO₄ standard (external), respectively. Elemental analyses wereprovided by Desert Analysis (Phoenix, Ariz.).

CDCl₃ solvents were purchased from Aldrich Chemical (Milwaukee, Wis.),distilled over calcium hydride, and vacuum transferred into an air-tightsolvent bulb prior to transfer into an inert-atmosphere glovebag. Allreactions were carried out under a dry nitrogen atmosphere usingstandard Schlenk techniques unless otherwise noted.

Cyclohexyl phosphine and 1,2-bis(phosphino)ethane were purchased fromStrem Chemicals, Inc. (Newburyport, Mass.) HCl (1.0 M in Et₂O solution),succinyl chloride, phthaloyl chloride, and diethyl L-tartrate werepurchased from Aldrich Chemical of Milwaukee, Wis. Acetyl chloride waspurchased from J. T. Baker (Phillipsburg, N.J.).

The aryl azine derivatives (aryl-CH═N—N═CH-aryl) were prepared byreaction of the corresponding aidehyde (2 equiv.) with hydrazine underrefluxing alcohol conditions. F. E. Hencoch, G. Hampton, C. R. Hauser,J. Am. Chem. Soc. 1969, 91, 676-681. The alkyl azine derivatives(alkyl—CH═N—N═CH-alkyl) (A. U. Blackham, N. L. Eatough, J. Am. Chem.Soc. 1962, 84, 2922-2930), phenylphosphine (R. C. Taylor, R. Kolodny, D.B. Walters, Synthesis in Inorganic and Metal-Organic Chemistry 1973,3,175-179), and o-bis(phosphino)benzene (E. P. Kyba, S.-T. Liu, R. L.Harris, Organometallics 1983, 2, 1877-1879) were prepared according toknown literature methods. Phenylphosphine is commercially available fromAldrich Chemical (Milwaukee, Wis.).

General Synthesis for Compounds 1a-g and 5

1a: R¹=Ph; R²═R³═Ph

1b: R¹=Ph; R²═R³=2-furanyl

1c: R¹=Ph; R²═R³=n-propyl

1d: R¹=Ph; R²═R³=i-propyl

1e: R¹=Ph; R²═R³=t-butyl

1f: R¹=Cyclohexyl; R²═R³═Ph

1g: R¹=Cyclohexyl; R²═R³=2-furanyl

A diethyl ether (20 mL) solution of the appropriate azine derivative(4.55 mmol) was treated with HCl (ca. 4.75 mL, 4.75 mmol, 1.0 M in Et₂Osolution) at 0° C. Immediately, a white solid precipitated fromsolution. Phenyl (or cyclohexyl for compounds 1f and 1g) phosphine (4.55mmol) was added to this suspension at 0° C. and the reaction mixture wasstirred for 4 hours (or overnight) at room temperature. Into theresultant white slurry was added a degassed 10% aqueous K₂CO₃ (ca 30 mL)solution at 0° C. The ether layer was separated via cannula, dried overMgSO₄, and filtered via cannula to obtain a colorless solution. Theether was evaporated under vacuum to yield the correspondingdiazaphospholanes.

rac-1a: Yield=67% of a white solid (rac/meso=13). ¹H NMR (CDCl₃): δ 4.53(b, 2H, NH), 5.11 (d, J_(H—P)=22.1 Hz, 1H, PCHN), 5.54 (s, 1H, PCHN),6.77 (m, 2H, Ph), 6.98 (m, 3H, Ph), 7.10-7.39 (m, 10H, Ph); ¹³C{¹H} NMR(CDCl₃): δ 71.51 (d, J_(C—P)=1.2 Hz, PCHN), 71.81 (d, J_(C—P)=5.7 Hz,PCHN), 126.29 (d, J_(C—P)=4.4 Hz, Ph), 126.37 (d, J_(C—P)=1.3 Hz),127.30 (s), 127.41 (s), 127.86 (s), 128.15 (d, J_(C—P)=6.3 Hz), 128.94(s), 128.98 (s), 133.34 (d, J_(C—P)=18 Hz), 134.53 (s), 141.10 (d,J_(C—P)=15.3 Hz), one quaternary carbon hasn't been assigned due to theoverlap; ³¹P NMR (CDCl₃): δ 21.4 (d, J_(P—H)=23 Hz). Analysis calculatedfor C₂₀H₁₉N₂P: C, 75.46; H, 6.02; N, 8.8. Found: C, 74.85; H, 6.09; N,8.8.

rac-1b: Yield=90% of a colorless oil (rac/meso=10). ¹H NMR (CDCl₃): δ4.0 (b, 1H, NH), 4.25 (b, 1H, NH), 4.84 (d, J_(H—P)=22.8 Hz, 1H, PCHN),5.24 (d, J_(H—P)=2.2 Hz, 1H, PCHN), 5.63 (m, 1H, furan), 6.1 (dd, J=1.8,3.3 Hz, 1H, furan), 6.31 (m, 1H, furan), 6.36 (m, 1H, furan), 7.12 (m,1H, furan), 7.33 (m, 5H, Ph), 7.42 (m, 1H, furan); ¹³C{¹H} NMR (CDCl₃):

64.46 (d, J=20.3 Hz, PCHN), 65.55 (d, J=24.8 Hz, PCHN), 106.28 (d, J=3.2Hz, furan), 107.13 (d, J=7 Hz, furan), 110.04 (s, furan), 110.55 (s,furan), 128.33 (d, J=7 Hz, Ph), 129.43 (s, Ph), 133.17 (d, J=18.5 Hz,Ph), 141.23 (s, furan), 142.62 (s, furan), 148 01 (furan), 150.09 (s,furan), 153.26 (d, J=14 Hz, Ph); ³¹P NMR (CDCl₃): δ 9.9 (d, J_(P—H)=23Hz). Analysis calculated for C₁₆H₁₅O₂N₂P: C, 64.43; H, 5.07; N, 9.39.Found: C, 64.59; H, 5.14; N, 8.70.

rac-1c: Yield=>90% of a white solid (rac/meso=5). ¹H NMR (CDCl₃): δ 0.82(t, J_(H—H)=7.3 Hz, 3H, CH₃), 0.94 (t, J_(H—H)=7.3 Hz, 3H, CH₃), 1.3-1.7(m, 8H, CH₂), 3.15 (doublet of tripet, J_(H—H)=7.0 Hz, J_(P—H)=16.2 Hz,1H, CH), 3.94 (t, J_(H—H)=6.5 Hz, 1H, CH), 3.3-3.6 (b, 2H, NH)7.34-7.41, (m, 3H, Ph), 7.47-7.55 (m, 2H, Ph); ¹³C{¹H} NMR (CDCl₃): δ13.9 (s, CH₃), 21.5 (d, J_(P—C)=12.0 Hz), 22.0 (d, J_(P—C)=6.6 Hz), 37.0(d, J_(P—C)=22.8 Hz), 67.0 (d, J_(P—C)=21.1 Hz, PCHN), CH (δ 67.3 (d,J_(P—C)=17.0 Hz, PCHN), 126.2 (d, J_(P—C)=6 Hz, C_(meta)), 127.0 (s,C_(para)), 133.8 (d, J_(P—C)=12 Hz, C_(ortho)), 136.8 (d, J_(P—C)=30 Hz,C_(ipso)); ³¹P NMR (CDCl₃): δ 1.1 (b). Analysis calculated forC₁₄H₂₃N₂P(hexane)_(0.1): C, 67.72; H, 9.5; N, 10.82. Found: C, 68.12; H,8.94; N, 10.72.

rac-1d: Yield=70% of a white solid with mainly a rac isomer. ¹H NMR(CDCl₃): δ 0.9-1.13 (m, 13H, CH and CH₃), 1.94 (m, 1H, CH), 2.81 (dd,J_(H—H)=9.0 Hz, J_(P—H)=26.4 Hz, 1H, PCHN), 3.82 (dd, J_(H—H)=6.3 Hz,J_(P—H)=1.9 Hz, 1H, PCHN), 3.2-3.6, (b, 2H, NH), 7.34-7.41, (m, 3H, Ph),7.47-7.55, (m, 2H, Ph); ¹³C{¹H} NMR (C₆D₆): δ 20.7, (d, J_(C—P)=13.7 Hz,CH₃), 21.4, (d, J_(C—P)=8.5 Hz, CH₃), 22.5 (d, J_(C—P)32 4.8 Hz, CH₃),23.5, (d, J_(C—P)=21.4 Hz, CH₃), 28.4 (s), 31.9 (d, J_(C—P)=20 Hz), 65.4(d, J_(C—P)=18 Hz), 67.5 (d, J_(C—P)=32 Hz), 77.1 (d, J_(C—P)=18.1 Hz,PCHN), 128.6 (d, J_(C—P)=7 Hz, C_(meta)), 129.1 (s, C_(para)), 134.9 (d,J_(C—P)=19 Hz, C_(ortho)), 135.9 (d, J_(C—P)=26 Hz, C_(ipso)); ³¹P NMR(CDCl₃): δ −5.7 (d, J_(P—H)=2.4 Hz). Analysis calculated forC₁₄H₂₃N₂P(CH₂Cl₂)_(0.1): C, 65.43; H, 9.04; N, 10.89. Found: C, 65.34;H, 8.61; N, 10.33.

rac-1e: Yield=61% of a white solid (rac/meso=6). ¹H NMR (CDCl₃): δ 0.75(d, J_(H—P)=1.1 Hz, 9H, CH₃), 1.04 (s, 9H, CH₃), 2.74 (d, J_(H—P)=21.3Hz, PCHN), 3.81 (d, J_(H—P)=2.6 Hz, 1H, PCHN), 7.34 (m, 3H, Ph), 7.58(m, 2H, Ph); ¹³C{¹H} NMR (CDCl₃): δ 28.11 (d, J_(C—P)=8.6 Hz, CH₃),29.27 (d, J_(C—P)=4.9 Hz, CH₃), 33.05 (s, CCH₃), 33.78 (d, J_(C—P)=15.9Hz, CCH₃), 79.54 (d, J_(C—P)=26.5 Hz, PCHN), 81.10 (d, J_(C—P)=19 Hz,PCHN), 128.55 (d, J_(C—P)=7.6 Hz, C_(ortho)), 129.31 (s, C_(para)),135.13 (d, J_(C—P)=19.7 Hz, C_(meta)), 136.49 (d, J_(C—P)=25.4 Hz,C_(ipso)); ³¹P NMR (CDCl₃):

−13.1 (d, J_(P—H)=19.8 Hz). Analysis calculated for C₁₆H₂₇N₂P: C, 69.03;H, 9.78; N, 10.06. Found: C, 69.3; H, 9.77; N, 9.91.

rac-1f: Yield=58% of a white solid with mainly a rac isomer. ¹H NMR(CDCl₃):

0.47 (m, 1H), 0.80 (m, 2H), 1.16-1.7 (m, 8H), 3.78 (b, 1H, NH), 4.14 (b,1H, NH), 4.78 (s, 1H, PCHN), 4.85 (d, J_(H—P)=19.1 Hz, 1H, PCHN),7.22-7.40 (m, 8H, Ph), 7.47-7.50 (m, 2H, Ph); ¹³C{¹H} NMR (CDCl₃): 26.2(s), 26.3 (d, J_(C—P)=12.8 Hz), 26.9 (d, J_(C—P)=7.7 Hz), 29.0 (d,J_(C—P)=8.3 Hz), 30.7 (d, J_(C—P)=19.5 Hz), 32.2 (d, J_(C—P)32 21.6Hz,), 70.62 (d, J_(C—P)=3.2 Hz, PCHN), 71.0 (s, PCHN), 126.4 (d,J_(C—P)=3.2 Hz, Ph), 126.8 (s, Ph), 127.4 (d, J_(C—P)=1.3 Hz, Ph), 127.7(d, J_(C—P)=9.5 Hz, Ph), 128.4 (s, Ph), 128.8 (s, Ph), 136.4 (s, CCH),140.4 (d, J_(C—P)=15.9 Hz, CCH); ³¹P NMR (CDCl₃):

11.68 (m). Analysis calculated for C₂₀H₂₅N₂P: C, 74.05; H, 7.77; N,8.64. Found: C, 74.4; H, 8.11; N, 9.67.

rac-1g: Yield=61% of a white solid with mainly a rac isomer. ¹H NMR(CDCl₃):

0.59 (m, 1H), 0.97 (m, 2H), 1.14-1.24 (m, 3H), 1.51-1.73 (m, 5H), 3.95(b, 2H, NH), 4.74 (d, J_(H—P)=3.3 Hz, 1H, PCHN), 4.82 (d, J_(H—P)=22.8Hz, PCHN), 6.23 (m, 1H), 6.29-6.35 (m, 3H), 7.37-7.39 (m, 2H); ¹³C{¹H}NMR (CDCl₃):

26.21 (s, CH₂), 26.47 (d, J_(C—P)=12.1 Hz), 26.75 (d, J_(C—P)=8.3 Hz),29.25 (d, J_(C—P)=10.2 Hz), 30.35 (d, J_(C—P)=19.1 Hz), 33.07 (d,J_(C—P)=30.0 Hz), 64.29 (d, J_(C—P)=28.6 Hz, PCHN), 65.0 (d,J_(C—P)=23.5 Hz, PCHN), 106.54 (d, J_(C—P)=2.6 Hz, furan), 107.25 (d,J_(C—P)=7.0 Hz, furan), 110.36 (s, furan), 110.63 (s, furan), 141.56 (s,furan), 142.52 (s, furan), 149.65 (s, PCCH), 153.11 (d, J_(C—P)=20.4 Hz,PCCH), ³P NMR (CDCl₃):

15.6 (d, J_(P—H)=21.3 Hz). Analysis calculated for C₁₆H₂₁N₂O₂P: C,63.15; H, 6.96; N, 9.2. Found: C, 63.26; H, 7.11; N, 9.25.

rac-5: Yield=79% of the crude product. X-ray quality crystals were grownfrom CH₂Cl₂/hexanes at room temperature. ¹H NMR (CDCl₃):

2.50 (s, 3H, CH₃), 2.51 (s, 3H, CH₃), 5.04 (d, J=8.8 Hz, 1H, NH), 5.53(dd, J=17.3, 8.8, Hz, 1H, PCHN), 6.32 (d, J=2.6 Hz, 1H, PCHN), 6.85-7.20(m, 11H, Ph), 7.28 (m, 1H, Ph), 7.43 (m, 1H, Ph), 9.50 (b, 1H, OH);¹³C{¹H} NMR (CDCl₃): δ 21.45 (s, CH₃), 21.77 (s, CH₃), 58.07 (d,J_(C—P)=19.7 Hz, PCHN), 61.40 (d, J_(C—P)=28.61 Hz, PCHN), 146.34 (s,Ph), 156.67 (d, J_(C—P)=5.5 Hz, Ph), 168.96 (s, CO), 171.17 (s, CO);Peaks at 118-135 ppm have not been assigned due to the complexity. ³¹PNMR (CDCl₃):

14.6 (m). Analysis calculated for C₂₄H₂₃N₂O₄P(CH₂Cl₂)_(0.25): C, 63.92;H, 5.2; N, 6.15. Found: C, 64.27; H, 4.96; N, 6.41.

Synthesis of Compounds 2a and 2b

2a: R¹=Ph; R²═R³=2-furanyl

2b: R¹=Cyclohexyl; R²═R³=2-furanyl

The appropriate azine (1.55 mmol) in Et₂O (50 mL) was treated withacetyl chloride (15.5 mmol, 10 equiv.) at 0° C. The appropriatephosphine (phenylphosphine (2a); cyclohexylphosphine (2b)) (1.55 mmol)was then slowly added at 0° C., and the mixture stirred at roomtemperature overnight. To the resultant white slurry was added 10%aqueous K₂CO₃ (ca. 20 mL) at 0° C. For 2a, the aqueous and organiclayers were filtered off via cannula to obtain a white solid which wasthen washed with distilled water and Et₂O. X-Ray quality crystals wereobtained from CH₂Cl₂ and hexane at room temperature. For 2b, the etherlayer was separated, dried over MgSO₄, and filtered off via cannula toobtain a colorless solution. The ether was then removed under reducedpressure to yield the corresponding diazaphospholane.

rac-2a: Yield=80% with a white solid with a mainly rac isomer. ¹H NMR(CDCl₃):

1.71 (s, 3H, CH₃), 2.21 (s, 3H, CH₃), 5.9 (dd, J=3.3, 1.8 Hz, 1H,furan), 6.03 (d, J=3.3 Hz, 1H, furan), 6.30 (dd, J=3.3, 1.8 Hz, furan),6.44 (d, J=3.3 Hz, 1H, furan), 6.55 (d, J_(H—P)=23.2 Hz, 1H, NCHP), 6.72(d, J_(H—P)=3.3 Hz, NCHP), 6.74 (m, 1H, furan), 7.11-7.22 (m, 5H, Ph),7.39 (m, 1H, furan); ¹³C{¹H} NMR (CDCl₃): δ 19.08 (s, CH₃), 20.68 (s,CH₃), 52.72 (d, J_(C—P)=19.7 Hz, NCHP), 56.75 (d, J_(C—P)=31.2 Hz,NCHP), 108.24 (d, J_(C—P)=2.5 Hz, furan), 109.91 (s, furan), 110.53 (d,J_(C—P)=10.2 Hz, furan), 110.83 (s, furan), 128.03 (d, J_(C—P)=7.0 Hz,C_(meta)), 129.38 (s, C_(para)), 132.51 (d, J_(C—P)=20.3 Hz, C_(ortho)),141.86 (s, furan), 143.51 (s, furan), 150.21 (d, J_(C—P)=32.4 Hz,C_(ipso)),171.80 (s, CO), 174.75 (s, CO), two carbons are not assignedprobably due to the overlap; ³¹P NMR (CDCl₃):

23.5 (d, J_(P—H)=22.9 Hz). Analysis calculated for C₂₀H₁₉N₂O₄P: C,62.83; H, 5.01; N, 7.33. Found: C, 62.91; H, 4.65; N, 7.21.

rac-2b: Yield=25% a white solid with mainly a rac isomer. ¹H NMR(CDCl₃):

0.43 (m, 1H), 0.75-1.0 (m, 2H), 1.1-1.3 (m, 3H), 1.5-1.8 (m, 5H), 1.68(s, 3H, CH₃), 2.22 (s, 3H, CH₃), 6.2-6.4 (m, 6H, furan and PCHN),7.3-7.4 (m, 2H, furan); ¹³C{¹H} NMR (CDCl₃):

19.42 (s, CH₃), 20.50 (s, CH₃), 26.00 (s), 26.29 (d, J_(C—P)=2.6 Hz),26.44 (d, J_(C—P)=5.1 Hz), 29.13 (d, J_(C—P)=19.1 Hz), 29.88 (d,J_(C—P)=12.8 Hz), 32.39 (d, J_(C—P)=19.1 Hz), 52.83 (d, J_(C—P)=22.9 Hz,PCHN), 54.29 (d, J_(C—P)=33.1 Hz, PCHN), 108.80 (s, furan), 110.27 (d,J_(C—P)=9.5 Hz, furan), 110.72 (s, furan), 110.88 (s, furan), 142.15 (s,furan), 143.14 (s, furan), 149.56 (d, J_(C—P)=3.2 Hz, furan), 150.75 (d,J_(C—P)=26.71 Hz, furan), 173.15 (s, CO), 174.77 (s, CO); ³¹P NMR(CDCl₃):

27.0 (m). Analysis calculated for C₂₀H₂₅N₂O₄P: C, 61.85; H, 6.49; N,7.21. Found: C, 62.18; H, 6.79; N, 7.30.

Synthesis of Compounds 3, 4, and 6

3: R¹=Ph; R²═R³=ferrocene

4a: R¹═R²═R³=Ph

4b: R¹=cyclohexyl; R²═R³=2-furanyl

6a: R²═R²═R³=Ph

6b: R¹=Ph; R²═R³=2-furanyl

6c: R¹=Ph; R²═R³=o-tolyl

6d: R¹=Ph; R²═R³=2-naphthyl

6e: R¹=Ph; R²═R³═C₆F₅

6f: R¹=Ph; R²═R³=n-propyl

6g: R¹=Ph; R²═R³=i-propyl

The appropriate azine (1.55 mmol) in Et₂O (50 mL) was treated with thediacid dichloride (4.65 mmol, 3 equiv.) at 0° C. The phosphine (1.55mmol) was then slowly added at 0° C., and the mixture was stirred atroom temperature overnight. To the resultant white slurry was added a10% aqueous K₂CO₃ solution (ca. 20 mL) at ice-bath temperature. For 3,4, 6a, 6b, and 6d, the aqueous and organic layers were filtered off viacannula to obtain a white solid. Subsequently, the product was washedwith distilled water and Et₂O, and the residue was dried in vacuo toobtain an analytically pure product. For 6c, 6e, 6f and 6g, the etherlayer was separated, dried over MgSO₄, and filtered off by cannulayielding the corresponding ether solution. The ether was removed invacuo to obtain the desired product. Compounds 6 can also be made fromthe addition of corresponding compound 1 into a THF solution ofphthaloyl chloride (3 equivalents) at ice-bath temperature. The mixturewas stirred overnight at room temperature, placed under reducedpressure, washed with Et₂O and degassed water, and dried overnight toyield the corresponding compound 6.

meso-3: Yield=69% of a reddish brown solid (rac/meso=0.6). X-ray qualitycrystals of meso-3 were grown from CH₂Cl₂/hexane at room temperature. ¹HNMR (CDCl₃):

2.50-2.6 (m, 2H, CH₂), 2.65-2.77 (m, 2H, CH₂), 3.88 (m, 2H, Cp), 4.0 (m,2H, Cp), 4.04 (m, 2H), 4.14 (s, Cp, 10H) 4.30 (m, 2H, Cp), 6.04 (s, 2H,CHN), 7.45 (m, 5H, Ph); ¹³C{¹H} NMR (CDCl₃):

29.3 (s, CH₂), 59.4 (d, J_(C—P)=24.2 Hz, PCHN), 67.73 (s, CH), 68.12 (sCH), 68.62 (d, J_(C—P)=10.8 Hz, PCHN), 69.1 (s, Cp), 70.4 (d,J_(C—P)=3.8 Hz, CH), 85.05 (d, J_(C—P)=19.7 Hz, CCH),129.2 (d,J_(C—P)=6.4 Hz, C_(meta)), 129.94 (s, C_(para)), 130.8 (d, J_(C—P)=15.8Hz, C_(ortho)), 134.2 (d, J_(C—P)=23.5 Hz, C_(ipso)), 165.2 (s, CO); ³¹PNMR (CDCl₃):

3.0 (s). Analysis calculated for C₃₂H₂₉N₂O₂Fe₂P(CH₂Cl₂)_(0.5) C,59.63;H, 4.55; N, 4.21; Found: C, 60.19 (61.10); H, 4.60 (4.37); N, 4.36(4.36).

rac-4a: Yield=95% of the crude product with mainly a rac isomer. X-rayquality crystals were grown from CH₂Cl₂/hexanes at room temperature. ¹HNMR (CDCl₃): δ 2.83 (m, 4H, CH₂) 5.82 (d, J_(H—P)=19.1 Hz, 1H, PCHN),6.51 (s, 1H, PCHN), 6.71-6.75 (m, 2H, Ph), 6.9-7.05 (m, 5H, Ph), 7.1-7.2(m, 2H,Ph), 7.25-7.30 (m, 1H, Ph), 7.30-7.38 (m, 3H, Ph), 7.42-7.46 (m,2H, Ph); ¹³C NMR (CDCl₃):

29.46 (s, CH₃), 30.38 (s, CH₃), 57.14 (d, J_(C—P)=21.0 Hz, PCHN), 61.72(d, J_(C—P)=31.8 Hz, PCHN), 124.79 (d, J_(C—P)=1.9 Hz, Ph), 125.41 (d,J_(C—P)=8.3 Hz, Ph), 126.57 (s, Ph), 127.85 (s, Ph), 128.10 (d,J_(C—P)=6.4 Hz, Ph), 129.07 (s, Ph), 129. 72 (s, Ph), 130.15 (d,J_(C—P)=24.2 Hz, Ph), 132.20 (d, J_(C—P)=19.0 Hz, Ph), 133.53 (s, Ph),137.10 (d, J_(C—P)=15.3 Hz, Ph), 165.24 (s, CO), 167.71 (s, CO), onepeak is not assigned due to the overlap; ³¹P NMR (CDCl₃):

11.6 (m). Analysis calculated for C₂₄H₂₁N₂O₂P: C, 71.99; H, 5.29; N,7.0. Found: C, 71.21; H, 5.29; N, 6.96.

rac-4b: Yield=59% of the crude product with mainly a rac isomer. X—Rayquality crystals were grown from CH₂Cl₂/hexanes at room temperature. ¹HNMR (CDCl₃):

0.75 (m, 1H), 1.0 (m, 2H), 1.25 (m, 3H), 1.6 (m, 3H), 1.8 (m, 2H),2.6-2.7 (m, 4H), 5.86 (d, J_(H,P)=14.8 Hz, 1H, PCHN), 5.96 (s, PCHN),6.26 (m, 1H, furan), 6.33 (d, J_(H,P)=1.5 Hz, 1H, furan), 6.36 (dd,J_(H—P)=1.9, 3.3 Hz, 1H, furan), 7.35 (m, 2H, furan); ¹³C{¹H} NMR(CDCl₃): δ 25.80 (d, J_(C—P)=1.3 Hz), 26.51 (s), 26.47 (d, J_(C—P)=20.3Hz), 28.49 (d, J_(C—P)=7 Hz), 29.47 (s), 29.76 (d, J_(C—P)=22.9 Hz),30.33 (s), 32.47 (d, J_(C—P)=21. Hz), 50.25 (d, J_(C—P)=24.2 Hz), 54.65(d, J_(C—P)=31.2 Hz), 107.16 (d, J_(C—P)=2.5 Hz), 107.76 (d, J_(C—P)=7Hz), 110.62 (s), 110.94 (s), 141.73 (d, J_(C—P)=1.3 Hz), 142.97 (s),147.45 (d, J_(C—P)=2.5 Hz), 150.21 (d, J_(C—P)=17.2 Hz), 165.55 (s, CO),167.59 (s, CO); 31P NMR (CDCl₃):

12.9 (m). Analysis calculated for C₂₀H₂₃N₂O₄P: C, 62.17; H, 6.0; N,7.25. Found: C, 62.04; H, 5.52; N, 7.16.

rac-6a: Yield=65% of a white solid with a rac isomer. X-ray qualitycrystals from grown from CH₂Cl₂/hexanes at room temperature. ¹H NMR(CDCl₃): δ 6.25 (d, 1H, J(H,P)=19.5 Hz, PCHN), 6.95 (s, 1H, PCHN), 7.05(m, 3H, Ph), 7.13-7.19 (m, 5H, Ph), 7.3-7.4 (m, 7H, Ph), 7.3-7.8 (m, 2H,CH), 8.44 (m, 1H, CH), 8.48 (m, 1H, CH), ¹³C{¹H} NMR (CDCl₃): δ 60.3 (d,J_(C—P)=19.7 Hz, PCHN), 64.9 (d, J_(C—P)=31.8 Hz, PCHN), 125.10 (d,J_(C—P)=3.2 Hz), 125.42 (d, J_(C—P)=6.3 Hz), 126.88 (d, J_(C—P)=1.9 Hz),127.83 (s), 127.94 (s), 128.06(d, J_(C—P)=2.6 Hz), 128.55 (d,J_(C—P)=7.0 Hz), 129.33 (d, J_(C—P)=1.3 Hz), 129.43 (s), 130.03 (s),130.22 (s), 130.35 (s), 130.46 (s), 132.85 (d, J_(C—P)=1.2 Hz), 132.939s), 133.188(s), 133.55 (d, J_(C—P)=8.3 Hz), 137.2 (d, J_(C—P)=14.6 Hz),156.30 (s, CO), 156.50(s, CO); 31P NMR (CDCl₃):

−1.3 (m). Analysis calculated for C₂₈H₂₁N₂O₂P: C, 74.99; H, 4.72; N,6.25. Found: C, 75.21; H, 4.64; N, 6.32.

rac-6b: Yield=71% of a white solid with mainly a rac isomer. X-rayquality crystals were grown from CH₂Cl₂/hexanes at room temperature. ¹HNMR (CDCl₃): δ 5.81 (m, 1H, furan), 6.09 (dd, J=3,2 Hz, 1H, furan), 6.32(m, 1H, furan), 6.44 (m, 1H, furan), 6.47(d, J_(H—P)=28 Hz, 1H, PCHN),6.73 (d, J_(H—P)=2 Hz, 1H, PCHN), 6.92 (m, 1H, furan), 7.3 (m, 5H, Ph),7.35 (m, 1H, furan), 7.77 (m, 2H, CH), 8.22 (m, 1H, CH), 8.36 (m, 1H,CH); ¹³C{¹H} NMR (CDCl₃): δ 54.7 (d, J_(C—P)=18 Hz, PCHN), 60.2 (d,J_(C—P)=30 Hz, PCHN), 107.2 (d, J_(C—P)=4 Hz, furan), 108.1 (d,J_(C—P)=6 Hz, furan), 110.5 (s, furan), 110.8 (s, furan), 127.7 (s, CH),127.8 (s, CH), 128.6 (d, J_(C—P)=8 Hz, Ph), 129.3 (s, CC═O), 130.2 (d,J_(C—P)=22 Hz, C_(ipso)), 130.5 (s, CC═O), 130.8 (s, Ph), 133.1 (s, CH),133.3 (d, J_(C—P)=10 Hz, Ph), 133.5 (s, CH), 141.6 (s, furan), 143.3 (s,furan), 145.8 (s, furan), 149.2 (d, J_(C—P)=13 Hz, furan), 156.3 (s, 2C,C═O); ³¹P NMR (CDCl₃):

−14.7 (b). Analysis calculated for C₂₄H₁₇N₂O₄P: C, 67.29; H, 4.0; N,6.54. Found: C, 66.99; H, 3.76; N, 6.39.

rac-6c: Yield=28% of a white solid (rac/meso=11). ¹H NMR (CDCl₃):

2.46 (s, 3H, CH₃), 2.47 (s, 3H, CH₃), 5.98 (d, J=9.3 Hz, 1H), 6.35 (d,J_(H—P)=18 Hz, 1H, PCHN), 6.48 (t, J=7 Hz, 1H), 6.79 (d, J=7.5 Hz, 1H),6.90 (s, 1H, PCHN), 6.85-7.3 (m, 10H), 7.84 (m, 2H, CH), 8.29 (m, 1H,CH), 8.39 (m, 1H, CH), How many H's; ¹³C{¹H} NMR (CDCl3): δ 20.4 (d,J_(C—P)=4 Hz, CH₃), 20.6 (d, J_(C—P)=7 Hz, CH₃), 59.0 (d, J_(C—P)=20 Hz,PCHN), 62.8 (d, J_(C—P)=32 Hz, PCHN), Peaks at 120-140 ppm have not beenassigned due to the complexity; ³¹P NMR (CDCl₃): δ −13.9 (d, J_(P—H)=17Hz). Analysis calculated for C₃₀H₂₅N₂O₂P(CH₂Cl₂)_(0.5): C, 70.59; H,5.05; N, 5.40. Found: C, 70.93; H, 4.93; N, 5.42

rac-6d: Yield (isolated)=24% of a white solid (rac/meso=11). ¹H NMR(CDCl₃):

6.41 (d, J_(H—P)=19 Hz, 1H, PCHN), 7.07 (s, 1H, PCHN), 8.30 (m, 1H, CH),8.46 (m, 1H, CH), 7.0-8.0 (m, 22H); ¹³C{¹H } NMR (CDCl₃):

61.2 (d, J_(C—P)=21 Hz, PCHN), 65.9 (d, J_(C—P)=31 Hz, PCHN), Peaks at120-140 ppm have not been assigned due to the complexity; ³¹P NMR(CDCl3): δ −2.6 (d, J_(P—H)=19 Hz). Analysis calculated for C₃₆H₂₅N₂O₂P:C, 78.82; H, 4.59; N, 5.11. Found: C, 78.21; H, 4.59; N, 5.19.

rac-6e: Yield=90% of a yellow solid (rac/meso=2). Recrystallization fromhexane gave the pure rac isomer (38%) and X-ray quality crystals ofrac-6e were obtained from slow evaporation of a hexane solution. ¹H NMR(CDCl₃): δ 6.65 (d, J_(H—P)=19.1 Hz, 1H, PCHN), 6.91 (d, J_(H—P)=4.1 Hz,1H, PCHN), 7.3=7.4 (m, 5H, Ph), 7.8 (m, 2H), 8.28 (m, 1H), 8.34 (m, 1H);¹³C{¹H} NMR (CDCl₃): δ 51.89 (d, J_(C—P)=22.3 Hz, PCHN), 57.01 (d,J_(C—P)=33.7 Hz, PCHN), 156.42 (s, CO), 156.58 (s, CO), peaks at 110-145ppm have not been assigned due to the complexity. ³¹P NMR (CDCl₃): δ−2.7 (m). Analysis calculated for C₂₈H₁₁N₂F₁₀O₂P: C, 53.52; H, 1.76; N,4.46. Found: C, 53.72; H, 2.01; N, 4.23.

rac-6f: Yield=80% of a yellow oil (rac/meso=4). ¹H NMR (CDCl₃):

0.75 (t, J_(H—H)=7 Hz, 3H CH₃), 0.92 (t, J_(H—H)=7 Hz, 3H, CH₃), 1.5 (m,4H, CH₂), 1.7 (m, 2H, CH₂), 1.9 (m, 2H, CH₂), 4.86 (ddd, J_(H—P)=21 Hz,J_(H—H)=12, 4 Hz, 1H, PCHN), 5.30 (dd, J_(H—H)=9, 5 Hz, 1H, PCHN),7.25-7.6 (m, 5H, aromatics), 7.6-8.1 (m, 2H, aromatics), 8.31 (m, 2H,aromatics); ¹³C NMR (CDCl₃):

14.4 (s, CH₃), 20.8 (d, J_(C—P)=10 Hz, CH₂), 21.4 (d, J_(C—P)=8 Hz,CH₂), 35.6 (s, CH₂), 35.8 (s, CH₂), 59.9 (d, J_(C—P)=17 Hz, PCHN), 62.9(d, J_(C—P)=27 Hz, PCHN), 128.0 (s), 128.3 (s), 129.6 (d, J_(C—P)=8 Hz),131.6 (s), 134.0 (d, J_(C—P)=12 Hz), 134.9 (s), 135.1 (s), A range of120-140 ppm has not been assigned due to the complexity; ³¹P NMR(CDCl₃): δ −18.9 (b). Analysis calculated for C₂₂H₂₅N₂O₂P: C, 69.46; H,6.62; N, 7.36. Found: C, 66.13; H, 4.96; N, 3.66.

rac-6g: Yield=49.9% of a white solid, prepared from the treatment of 1dand phthaloyl chloride in THF. ¹H NMR (CDCl₃): δ 0.41, (d, J_(H—H)=7.1Hz, 3H, CH₃), 0.95-1.06 (m, 9H, CH₃) 2.41, (oct, J_(H—H)=6.8 Hz, 1H,CHMe₂), 3.13, (oct, J_(H—H)=6.9 Hz, 1H, CHMe₂), 4.94 (dd, J_(H—H)=5.8Hz, J_(P—H)=20.4 Hz, 1H, PCHN), 5.32 (dd, J_(H—H)=6.2 Hz, J_(P—H)=1.7Hz, 1H, PCHN), 7.30-7.45, (m, 3H), 7.60-7.68, (m, 2H), 7.79-7.89, (m,2H), 8.30-8.44, (m, 2H); ¹³C{¹H} NMR (CDCl₃):

18.0 (d, J_(P—C)=1.0 Hz, CH₃), 18.7 (d, J_(P—C)=10.0 Hz, CH₃), 19.8, (dJ_(P—C)=8.86 Hz, CH₃), 20.2 (d, J_(P—C)=10.0 Hz, CH₃), 22.5 (d,J_(P—C)=4.8 Hz, CH₃), 23.5 (d, J_(P—C)=21.4 Hz, CH₃), 65.7 (d,J_(P—C)=17.6 Hz, PCHN), 67.8 d, J_(P—C)=32.0 Hz, PCHN), 157.6 (s, CO),156.7 (s, CO); peaks at 127.4-135.1 ppm have not been assigned due tothe complexity. ³¹P NMR (CDCl₃): δ −25.7. Analysis calculated forC₂₂H₂₅N₂O₂P: C, 69.46; H, 6.62; N, 7.36. Found: C, 69.45; H, 6.31; N,7.42.

General Synthesis of Compounds 7 and 9

Phenyl azine (322.4 mg, 1.55 mmol) in Et₂O (50 mL) was treated with HCl(0.78 mL, 2M Et2O solution) at 0° C. The corresponding bis-phosphine(1,2-diphosphinobenzene (7); 1,2-diphosphinoethane (9)) (0.775 mmol) wasthen slowly added at 0° C., and the mixture was stirred at roomtemperature overnight. To the resultant white slurry was added a 10%aqueous K₂CO₃ solution (ca. 20 mL) at ice-bath temperature. The aqueousand organic layers were filtered off via cannula to obtain a white solidwhich was subsequently washed with distilled water and Et₂O. The whitesolid was dried overnight under vacuum to obtain analytically purecompound 7. X-ray quality crystals for rac-7 were grown from CH₂Cl₂ andhexanes at room temperature.

rac-7: Yield=32% of a white solid. ¹H NMR (CDCl₃): δ 3.75 (dd,J_(H—H)=6.6, 10.3 Hz, 2H, NH), 4.34 (t, J_(H—H)=11.4 Hz, 2H, NH), 4.55(d, J_(H—H)=6.3 Hz, 2H, PCHN), 4.71 (q, J=11.7, 2H, PCHN), 6.63 (m, 4H),6.80 (m, 4H), 6.94 (m, 2H), 7.23-7.40 (m, 14H); ¹³C{¹H} NMR (CDCl₃): δ70.40 (t, J_(C—P)=6.4 Hz, PCHN), 71.27 (t, J_(C—P)=14.0 Hz, PCHN),126.40 (t, J_(C—P)=2.5 Hz), 126.58 (s), 127.47 (s), 128.75 (s), 129.24(s), 131.72 (s), 134.98 (s), 141.08 (t, J_(C—P)=8.3 Hz), 141.5 (s).Peaks at 127-128 ppm haven't been assigned due to the complexity. ³¹PNMR (CDCl₃):

11.6 (t, J_(P—H)=10.7 Hz). Analysis calculated for C₃₄H₃₂N₄P₂: C, 73.11;H, 5.77; N, 10.03. Found: C, 73.05; H, 5.74; N, 10.1.

rac-9: Yield=32% of a white solid. ¹H NMR (CDCl₃): δ 0.95 (m, 4H, CH2),3.76 (dd, J_(H—H)=7.0, 11.0 Hz, 2H, NH), 4.11 (t, J=10.3 Hz, 2H, NH),4.41 (d, J_(H—H)=7.0 Hz, 2H, PCHN), 4.82 (q, J=10.3 Hz, 2H, PCHN),7.28-7.40 (m, 6H, Ph), 7.50 (m, 4H, Ph); ¹³C{¹H} NMR (CDCl₃): δ 19.8 (d,J_(C—P)=7 Hz, CH₂P), 69.7 (dd, J_(C—P)=10.8, 14 Hz, PCHN), 73.3 (t,J_(C—P)=11.4 Hz, PCHN), 126.1 (s), 126.7 (s), 127.44 (s), 127.6 (d,J_(C—P)=11 Hz),128.57 (s), 128.83 (s), 136.4 (s, C_(ipso)), 139.9 (t,J_(C—P)=8.3 Hz, C_(ipso)); ³¹P NMR (CDCl₃): δ 15.8 (m). Analysiscalculated or C₃₀H₃₂N₄P₂: C, 70.58; H, 6.32; N, 10.97. Found: C, 70.29;H, 6.31; N, 11.0.

Synthesis of rac-8 Compound

1,2-Bis(phosphino)benzene (0.2 mL, 1.55 mmol) was added to the ethersolution of phenyl azine (648 mg, 3.1 mmol) and phthalolyl chloride (0.9mL, 6.25 mmol) at 0° C. After the mixture stirred over night, an aqueous10% K₂CO₃ solution (30 mL) was added into the resultant white slurry atice-bath temperature. The aqueous and ether layers were removed viacannula and the residue dried in vacuo. The residue was washed with THFand Et₂O (1:1 (v/v)) to obtain a white solid of rac-8 in a 23% yield.X-ray quality crystals were grown from CH₂Cl₂/hexanes at roomtemperature. In addition, rac-8 was made from the addition of rac-7 intophthaloyl chloride in THF at 0° C. ¹H NMR (CDCl₃): δ 6.15 (t,J_(P—H)=10.3 Hz, 2H, PCHN), 6.18 (s, 2H, PCHN), 6.96 (m, 4H), 7.1 (m,4H), 7.17 (m, 2H), 7.3-7.4 (m, 14H), 7.8 (m, 4H), 8.2 (m, 2H, CH), 8.36(m, 2H, CH); ¹³C{¹H} NMR (CDCl₃): δ 60.56 (s, PCHN), 65.75 (t,J_(C—P)=18.5 Hz, PCHN), 156.86 (s, CO), 157.11 (s, CO), Peaks at 125-140ppm haven't been assigned due to the complexity; ³¹P NMR (CDCl₃):

−14.4 (t, J_(P—H)=10.7 Hz). Analysis calculated forC₅₀H₃₆N₄O₄P₂(CH₂Cl₂)_(0.8): C, 68.81; H, 4.27; N, 6.32. Found: C, 68.55;H, 4.37; N, 6.14.

Resolution Procedure for Tartaric Acid Derivatives: Tart-1a, Tart-1e,and Tart-9

Di-O-methyl-tartaric acid was prepared according to the literaturemethod. I. Felner, K. Schenker, Helv. Chim. Acta. 1970, 53, 4, 754-762.The acid was converted to the acid chloride based loosely on literatureprocedure. T. Purdie, C. R. Young, J. Chem. Soc. 1910, 1532. The acidwas slowly added to a slight excess of PCl₅ in benzene at 0° C. undernitrogen followed by stirring overnight. The resulting solution wasfiltered and solvent was removed in vacuo to yield a yellow solid. Thesolid was purified by sublimation. ¹H NMR (CDCl₃): 3.57 (s, 6H), 4.73(s, 2H); ¹³C {¹H} NMR (CDCl₃): δ 60.5, 87.4, 169.3.

A THF solution of the acid chloride was added dropwise to a stirring THFsolution of the diazaphospholane at room temperature. After stirringovernight, the THF was removed in vacuo. Ether was added to theresulting oil, and to the resulting solution was added aqueous 10%K₂CO₃. The ether layer was dried over MgSO₄, and the ether was removedin vacuo. Resolution of the Tart-9 diastereomers was accomplished onAldrich silica preparative TLC plates (20 cm×20 cm×1 mm) with a mobilephase of ethyl acetate/hexane. Both diastereomers were separatelyrecovered. Resolution of Tart-1a and Tart-1e was accomplished by flashchromatography using a column packed with Silica Gel 60 (EM Science) andeluents of 15:1 and 30:1 CH₂Cl₂/ethyl acetate. One diastereomer of eachwas cleanly recovered. The other diastereomers each had unidentifiedimpurities in ¹H and ³¹P NMR's. Absolute configurations of the resolveddiastereomers are not currently known.

Tart-9: [Crude product has only 2 peaks in ³¹P NMR] (R_(f)=0.17): ¹H NMR(CDCl₃): 0.95 (m, 4H, CH₂), 3.61 (s, 6H, OCH₃), 3.75 (s, 6H, OCH₃), 3.89(d, J_(H—H)=12 Hz, 2H, CHOCH₃), 4.27 (d, J_(H—H)=12 Hz, 2H, CHOCH₃),5.56 (s, 2H, PCHN), 5.56 (d, J_(H—P)=16 Hz, 2H, PCHN), 6.9-7.4 (m, 30H);³¹P NMR (CDCl₃): δ 4.7 (m); (R_(f)=0.28): ¹H NMR (CDCl₃): 3.41 (s, 6H,OCH₃), 3.61 (s, 6H, OCH₃), 3.88 (d, J_(H—H)=3 Hz, 2H, CHOCH₃), 3.97 (d,J_(H—H)=3 Hz, 2H, CHOCH₃), 5.42 (d, J_(H—P)=17 Hz, 2H, PCHN), 5.57 (s,2H, PCHN), 6.9-7.4 (m, 30H); ³¹P NMR (CDCl₃): δ 3.5 (m).

Tart-1a: [Crude product has two diastereomers as main products withseveral unidentified impurities] (R_(f)=0.33): ¹H NMR (CDCl₃): 3.58 (s,3H, OCH₃), 3.71 (s, 3H, OCH₃), 3.97 (d, J_(H—H)=12 Hz, 1H, CHOCH₃), 4.17(d, J_(H—H)=12 Hz, 1H, CHOCH₃), 5.80 (d, J_(H—P)=19 Hz, 1H, PCHN), 6.38(s, 1H, PCHN), 6.6-7.4 (m, 15H); ³¹P NMR (CDCl₃): δ 9.2 (m) with a traceof other impurities; (R_(f)=0.55): ¹H NMR (CDCl₃): 3.47 (s, 3H, OCH₃),3.57 (s, 3H, OCH₃), 3.86 (d, J_(H—H)=4 Hz, 1H, CHOCH₃), 4.00 (d,J_(H—H)=4 Hz, 1H, CHOCH₃), 5.71 (d, J_(H—P)=19 Hz, 1H, PCHN), 6.42 (s,1H, PCHN), 6.6-7.5 (m, 15H); ³¹P NMR (CDCl₃): δ 8.5 (m).

Tart-1e: [Crude product has two diastereomers as main products withseveral unidentified impurities] (R_(f)=0.31): ¹H NMR (CDCl₃): 0.84 (d,J_(H—P)=1 Hz, 9H, C(CH₃)₃), 0.98 (s, 9H, C(CH₃)₃), 3.51 (s, 3H, OCH₃),3.53 (s, 3H, OCH₃), 3.86 (d, J_(H—H)=3 Hz, 1H, CHOCH₃), 3.94 (d,J_(H—H)=3 Hz, 1H, CHOCH₃), 4.58 (d, J_(H—P)=21 Hz, 1H, PCHN), 4.74 (d,J_(H—P)=3 Hz, 1H, PCHN), 7.2-7.7 (m, 5H); ³¹P NMR (CDCl₃): δ 1.4;(R_(f)=0.15): ¹H NMR (CDCl₃): 0.78 (d, J_(H—P)=1 Hz, 9H, C(CH₃)₃), 0.96(s, 9H, C(CH₃)₃), 3.68 (s, 3H, OCH₃), 3.72 (s, 3H, OCH₃), 3.99 (d,J_(H—H)=11 Hz, 1H, CHOCH₃), 4.25 (d, J_(H—H)=11 Hz, 1H, CHOCH₃), 4.53 d,J_(H—P)=21 Hz, 1H, PCHN), 4.81 (d, J_(H—P)=3 Hz, PCHN), 7.2-7.7 (m, H);³¹P NMR (CDCl₃): δ 4.8 plus one impurity with peak height ratio about5:1 product to impurity at δ −6.2.

Reaction of an Acid Dichloride with a Diimine

All manipulations were performed under a N₂ atmosphere and usingstandard Schlenk techniques.

Two equivalents of phthaloyl dichloride were added dropwise to a stirredether solution of the azine (970 mg) formed by the reaction ofequivalents of 2-methyl benzaldehyde with hydrazine. After stirringovernight, the solution was set aside. After 5 days, 100 mg of crystalshad formed which were characterized using X-ray crystallographicanalysis.

Synthesis of Diazaphospholane from Dichloro Compound

All manipulations were performed under N₂ using standard Schlenktechniques.

A solution of the azine (383 mg in 100 mL Et₂O) prepared from 2-methylbenzaldehyde and hydrazine was treated with 2 equivalents of phthaloyldichloride and stirred overnight. Phenylphosphine (170 mg) was slowlyadded, and the solution was stirred overnight. To the resultant solutionwas added a 10% aqueous solution of K₂CO₃. The ether layer wasseparated, dried over MgSO₄, and filtered using a glass frit. The etherwas removed, and 400 mg of the diazaphospholane was obtained as a 10:1rac:meso mixture.

Synthesis of Diimine from trans-1,2-Diaminocyclohexane and2-Naphthaldehyde

Trans-1,2-diaminocyclohexane (2.0 mL) was added dropwise to stirredsolution of two equivalents of 2-naphthaldehyde (8.2 g in 100 mLbenzene). After stirring for one hour, the solution was heated to 50° C.for 30 minutes. The solvent was removed on a rotary evaporator. Theresulting solid was redissolved in benzene and was then removed byrotary evaporation to azeotropically remove water. This procedure wasrepeated once more. The remaining solid was rinsed eight times with 25mL of ether and filtered. The remaining solid was dried under vacuum for15 minutes and was used without further purification (yield=5.17 g).

Synthesis of Diazaphosphacycle from Diimine formed fromtrans-1,2-Diaminocyclohexane and 2-Naphthaldehyde

All manipulations were performed under N₂ using standard Schlenktechniques

Phenyl phosphine (0.3 mL) was added dropwise to a stirred solution ofthe diimine formed from trans-1,2-diaminocyclohexane and benzaldehyde(1.06 g in 100 mL THF). After 10 minutes, an HCl solution (1.36 mL of a2M solution in ether) was added dropwise. The resulting solution wasthen stirred for 18 hours. THF was removed under vacuum and 75 mL ofether was added. A 10% aqueous solution of K₂CO₃ was added to the ethermixture and was stirred until all solid had gone into solution. Theether layer was separated, dried over MgSO₄, and filtered. The ether wasthen removed under vacuum to yield a solid product (crude yield=1.31 g)consisting of two diastereomers. ³¹P NMR (CDCl₃): δ 19, 9.

Synthesis of an η³-allyl Pd Complex with a Bidentate Diazaphospholane

To a Teflon® brand fluorinated polymer capped NMR tube was added[(η³—C₃H₅)PdCl]₂ (5.2 μmol) (Aldrich Chemical (Milwaukee, Wis.)) and thediazaphospholane (10.3 μmol) indicated in the above structure. CD₂Cl₂(ca 1 mL) was added, and the NMR tube was agitated until the solids wentinto solution. The designated Pd complex was obtained and characterizedby NMR. ¹H NMR (CD₂Cl₂): δ 3.4 (allyl CH₂), 4.9 (allyl CH), 6.4 (PCHN),6.6-7.6 (unassigned), 7.9 (phthaloyl), 8.3 (phthaloyl); ³¹P NMR: δ 71ppm.

Synthesis of a Dimethyl Pt Complex with a Bidentate Diazaphospholane

To a Teflon® brand fluorinated polymer capped NMR tube was added,[(cyclooctadiene)Pt(CH₃)₂] (1.3 μmol) (Aldrich Chemical (Milwaukee,Wis.) and the diazaphospholane (1.2 μmol) indicated by the abovestructure. Approximately 1 mL of C₆D₆ was added and the NMR tube wasagitated until the solids went into solution. The solution wasevaporated to dryness in vacuo to remove free cyclooctadiene, andapproximately 1 mL of C₆D₆ was added. The dimethyl Pt complex indicatedabove was characterized by NMR. ¹H NMR (C₆D₆): δ 0.6 (CH₃), 0.2-1.6(broad ethyl peaks unassigned), 5.8 PCHN), 6.6 (PCHN), 6.7-7.4(aromatics), 8.4 (phthaloyl); ³¹P NMR: δ 63 (with ¹⁹⁵Pt satellites;J_(Pt—P)=1680 Hz).

Synthesis of Rhodium(diazaphospholane)Cl(norbornadiene)

A CH₂Cl₂ solution of 2,5-diphenyldiazaphospholane (100 mg, 0.224 mmol)was added into a CH₂Cl₂ solution of [Rh(norbornadiene)Cl]₂ (51.7 mg,0.112 mmol) at room temperature. The resulting mixture was stirred for 1hour and pumped on under vacuum to quantitatively yield a red-orangesolid. X-ray quality crystals were obtained from CH₂Cl₂ and hexane atroom temperature. The Rh complex indicated above was characterized byX-ray crystallography and NMR spectroscopy. ¹H NMR (CDCl₃): δ 1.33 (s,2H), 3.04 (m 1H), 3.34 (m, 1H), 3.50 (m, 1H), 3.60 (m, 1H), 5.09 (m,1H), 5.22 (m, 1H), 6.9-7.0 (m, 5H), 7.1-7.43 (m, 9H), 7.50 (m, 3H), 7.79(m, 5H), 8.24 (m, 1H), 8.32 (m, 1H); ³¹P{¹H} NMR (CDCl₃): δ 45.0 (d,J_(Rh—P)=189 Hz).

Synthesis of [{1,2-bis(diazaphospholanes)benzene}RhCl]₂

A CH₂Cl₂ solution of 1,2-bis(diazaphospholanes)benzene as indicated inthe above structure was added into a [Rh(norbornadiene)Cl]₂ (preparedaccording to known procedure see E. W. Abel, M. A. Bennet, G. Wilkinson,J. Chem. Soc. 1959, 3178-3182 and available from Aldrich Chemical(Milwaukee, Wis.)) (or [Rh(COD)Cl]₂) (prepared according to knownprocedure see G. Giordano, R. H. Crabtree, Inorg. Synth. 1990, 28 88-90and available from Strem Chemicals, Inc. (Newburyport, Mass.)) solutionin CH₂Cl₂ at room temperature. The reaction mixture was stirred for 1hour and pumped on under vacuum to quantitatively yield a red-orangesolid. X-ray quality crystals were obtained from CH₂Cl₂ and hexane atroom temperature. The dirhodium complex indicated above wascharacterized by X-ray crystallography and NMR spectroscopy. ¹H NMR(CDCl₃): δ 5.71 (br, 2H), 6.16 (s, 2H), 7.1-7.3 (m, 14H), 7.47 (m, 6H),7.88 (m, 4H), 8.32 (m, 2H), 8.40 (m, 2H); ³¹P{¹H} NMR (CDCl₃): δ 87.7(d, J_(Rh—P)=209 Hz).

Synthesis of {Rhodium[1,2-bis(diazaphospholanes)benzene](COD)}BF₄

A 1:1 mixture of [Rh(COD)₂]BF₄ (prepared according to known proceduresee T. G. Schenck, J. M. Downes, C. R. Miline, P. B. Mackenzie, M.Boucher, J. Wheland, B. Bosnich, Inorg. Chem. 1985, 24 2334-2337 andavailable from Pressure Chemical Co. (Pittsburgh, Pa.)) and1,2-bis(diazaphospholanes)benzene was prepared in an NMR tube at roomtemperature. After CDCl₃ was added, the mixture was agitated well.³¹P{¹H} NMR indicated that the initial product wasRh[bis(diazaphospholanes)benzene](COD)}BF₄ showing a resonance signal at62.2 ppm (J_(Rh—P)=163 Hz). After 2 days, a new resonance signalappeared at 87.7 ppm (J_(Rh—P)=209 Hz), which was identified as[{1,2-bis(diazaphospholanes)benzene}RhCl]₂

Catalytic Allylic Alkylation

For the purposes of this example, the numbers refer to the numbers ofthe compounds in the reaction scheme presented above except as otherwisenoted.

All manipulations were performed under a N₂ atmosphere.

A vial was prepared with 2.8 mg of [Pd(η³—C₃H₅)Cl]₂ (Aldrich Chemical(Milwaukee, Wis.)) and 15.0 mg of the diazaphospholane (3) (Example 8)in 1 mL CH₂Cl₂. A second vial was prepared with 1.0 mmol of cinnamylacetate (1), 3.0 mmol of dimethyl malonate (2), 3.0 mmol ofN,O-bis(trimethylsilyl)acetamide₂ (Aldrich Chemical (Milwaukee, Wis.)),and two grains of potassium acetate in 1 mL of CH₂Cl₂. The second vialwas added to the first vial and the solution was stirred for 18 hours atambient temperature. The solvent was removed under vacuum and the ¹H NMRof the product dissolved in CDCl₃ was taken. As determined by NMR, theconversion of cinnamyl acetate to alkylated products 4 and 5 was >98%with a 33:1 ratio of 5:4.

Hydrogenation of Methylacetamidoacrylate

Under a N₂ atmosphere, a mixture of 1,2-bis(diazaphospholane)ethane(3.85 mg, 0.005 mmol) and [Rh(COD)₂]BF₄ (2 mg, 0.005 mmol) 2 (PressureChemical Co. Pittsburgh, Pa.)) in THF (3 mL) was stirred for 1 hour atroom temperature. Next, methylacetamidoacrylate (14.3 mg, 0.1 mmol)₂(Sigma-Aldrich (St. Louis, Mo.)) in THF(3 mL) was added and hydrogen(H₂) bubbled for 30 minutes at room temperature. The reaction flask wasthen sealed and stirred overnight. The reaction was then filteredthrough a short path of silica gel (150 mg) and washed with CH₂Cl₂ (5mL). The hydrogenated product with complete conversion was identifiedusing GC chromatography (FIG. 8) which shows the hydrogenation productof the hydrogenation using a chiral GC column with a racemic mixture ofthe catalyst.

All references cited herein are specifically incorporated by referenceinto the disclosure of this application.

It is understood that the invention is not limited to the embodimentsset forth herein for illustration, but embraces all such forms thereofas come within the scope of the claims.

1. A method of synthesizing a diazaphosphacycle, comprising: reacting aphosphine with a diimine and optionally one or more equivalents of anacid halide, a sulfonyl halide, a phosphoryl halide, or an acidanhydride in the substantial absence of O₂ to form thediazaphosphacycle, wherein the phosphine has the formula I

wherein, R¹ is selected from the group consisting of substituted andunsubstituted aryl groups, substituted and unsubstituted alkyl groups,substituted and unsubstituted alkenyl groups, substituted andunsubstituted cycloalkyl groups, and substituted and unsubstitutedferrocenyl groups.
 2. The method of claim 1, wherein the diimine has theformula II, and the diazaphosphacycle has the formula III,

wherein, R² and R³ are independently selected from the group consistingof substituted and unsubstituted aryl groups, substituted andunsubstituted alkyl groups, substituted and unsubstituted cycloalkylgroups, substituted and unsubstituted heterocyclyl groups, andsubstituted and unsubstituted ferrocenyl groups; R⁴ is selected from thegroup consisting of —H, substituted and unsubstituted alkyl groups,substituted and unsubstituted cycloalkyl groups, substituted andunsubstituted aryl groups, trialkylsilyl groups, triarylsilyl groups,alkyldiarylsilyl groups, dialkylarylsilyl groups, —C(═O)—R⁶ groups,—S(═O)₂—R⁶ groups, —P(═O)R⁶R⁷ groups, and —C(═NR⁶)—R⁷ groups; R⁵ isselected from the group consisting of —H, substituted and unsubstitutedalkyl groups, substituted and unsubstituted cycloalkyl groups,substituted and unsubstituted aryl groups, trialkylsilyl groups,triarylsilyl groups, alkyldiarylsilyl groups, dialkylarylsilyl groups,—C(═O)—R⁷ groups, —S(═O)₂—R⁶ groups, —P(═O)R⁶R⁷ groups, and —C(═NR⁶)—R⁷groups; R⁶is selected from the group consisting of substituted andunsubstituted alkyl groups, substituted and unsubstituted alkenylgroups, substituted and unsubstituted cycloalkyl groups, substituted andunsubstituted aryl groups, —OH groups, substituted and unsubstitutedalkoxy groups, substituted and unsubstituted aryloxy groups, —NH(alkyl)groups, —NH(aryl) groups, —N(aryl)₂ groups, —N(alkyl)₂ groups,—N(alkyl)(aryl) groups, —S-alkyl groups, and S-aryl groups; R⁷ isselected from the group consisting of substituted and unsubstitutedalkyl groups, substituted and unsubstituted alkenyl groups, substitutedand unsubstituted cycloalkyl groups, substituted and unsubstituted arylgroups, —OH groups, substituted and unsubstituted alkoxy groups,substituted and unsubstituted aryloxy groups, —NH(alkyl) groups,—NH(aryl) groups, —N(aryl)₂ groups, —N(alkyl)₂ groups, —N(alkyl)(aryl)groups, —S-alkyl groups, and S-aryl groups; R⁶ and R⁷ may be part of thesame alkyl group, alkenyl group, or aryl group such that R⁴ and R⁵together with the two nitrogen atoms of the diazaphosphacycle form aring; and Y is a linking group selected from the group consisting ofsubstituted and unsubstituted cycloalkyl groups, substituted andunsubstituted aryl groups, substituted and unsubstituted alkenyl groups,silyl groups, substituted alkyl groups, and groups having the formula—(CH₂)_(n)— wherein n is selected from the group consisting of 0, 1, 2,and
 3. 3. The method of claim 2, wherein n is
 0. 4. The method of claim2, wherein Y is a cycloalkyl group, wherein one of the N atoms of thediimine is bonded to a first ring member C atom of the cycloalkyl groupand the other N atom of the diimine is bonded to a second ring member Catom that is bonded to the first ring member C atom.
 5. The method ofclaim 2, wherein Y has the formula

and the benzene ring of Y may be additionally substituted.
 6. The methodof claim 2, wherein R² and R³ are identical but are not part of the samegroup.
 7. The method of claim 2, wherein the diazaphosphacycle isselected from the group consisting of compounds of formula IIIA,compounds of formula IIIB, and mixtures thereof,


8. The method of claim 7, wherein n is
 0. 9. The method of claim 2,wherein the diazaphosphacycle has the formula IIIC,


10. The method of claim 9, wherein n is
 0. 11. The method of claim 1,wherein the phosphine and the diimine are reacted in the presence of anacid.
 12. The method of claim 2, wherein the phosphine and the diimineare reacted in the presence of the acid halide, the sulfonyl halide, thephosphoryl halide, or the acid anhydride, and at least one of R⁴ and R⁵is not H.
 13. The method of claim 2, wherein the phosphine and thediimine are reacted in the presence of the acid halide, and furtherwherein R⁴ is a —C(═O)—R⁶ group and R⁵ is a —C(═O)—R⁷ group.
 14. Themethod of claim 1, wherein the phosphine and the diimine are reacted inthe presence of phthaloyl dichloride or phthaloyl dibromide.
 15. Themethod of claim 1, wherein R¹ comprises one or more —PH₂ group such thatthe phosphine is a polyphosphine.
 16. The method of claim 15, whereinthe polyphosphine is selected from the group consisting of1,2-diphosphinoethane, 1,2-diphosphinoethylene, 1,3-diphosphinopropane,substituted and unsubstituted 1,2-diphosphinobenzene groups, substitutedand unsubstituted 1,8-diphosphinoanthracene groups, substituted andunsubstituted 1,8-diphosphino-9,10-dihydroanthracene groups, substitutedand unsubstituted 1,8-diphosphinoxanthene groups, and substituted andunsubstituted 1,1′-diphosphinoferrocene groups.
 17. The method of claim1, wherein the phosphine, the diimine, and optionally the acid halideare reacted in a substantially deoxygenated solvent comprising an ether,an alcohol, water, dichloroethane, or combinations thereof.
 18. Themethod of claim 1, further comprising reacting an acid halide, an acidanhydride, a phosphoryl halide, or a sulfonyl halide with thediazaphosphacycle to produce a second diazaphosphacycle wherein R⁴ andR⁵ are both —H in the diazaphosphacycle and at least one of R⁴ and R⁵ isnot —H in the second diazaphosphacycle.
 19. A method of synthesizing adiazaphosphacycle transition metal complex, comprising: (a) synthesizingthe diazaphosphacycle according to the method of claim 1; (b) reactingthe diazaphosphacycle with a starting transition metal complex toprovide the diazaphosphacycle transition metal complex.
 20. The methodof claim 19, wherein the starting transition metal complex includes atleast one ligand that is replaced by the diazaphosphacycle.
 21. A methodof synthesizing a diazaphosphacycle, comprising: (a) reacting a diiminewith an acid halide, a diacid dihalide, a sulfonyl halide, a disulfonyldihalide, a phosphoryl halide, or a diphosphoryl dihalide to form adihalo intermediate compound; and (b) reacting the dihalo intermediatecompound with a phosphine of formula R¹—PH₂ in the substantial absenceof O₂ to form the diazaphosphacycle, wherein R¹ is selected from thegroup consisting of substituted and unsubstituted aryl groups,substituted and unsubstituted alkyl groups, substituted andunsubstituted alkenyl groups, substituted and unsubstituted cycloalkylgroups, and substituted and unsubstituted ferrocenyl groups; and thediimine has the formula IV

wherein R⁸ and R⁹ are independently selected from the group consistingof substituted and unsubstituted aryl groups, substituted andunsubstituted alkyl groups, substituted and unsubstituted cycloalkylgroups, substituted and unsubstituted heterocyclyl groups, andsubstituted and unsubstituted ferrocenyl groups.
 22. The method of claim21, wherein the diimine is reacted with a diacyl dihalide, and thediacyl dihalide has the formula V or the formula VI

and the diazaphosphacycle has the formula VII or the formula VIII

wherein, R¹⁰, R¹¹, R¹², and R¹³ are independently selected from thegroup consisting of —H, substituted and unsubstituted alkyl groups,substituted and unsubstituted cycloalkyl groups, and substituted andunsubstituted aryl groups; R¹⁰ and R¹¹ may join together to form asubstituted or unsubstituted aryl group or a substituted orunsubstituted cycloalkenyl group; R¹² and R¹³ may join together to forma substituted or unsubstituted cycloalkenyl group or a substituted orunsubstituted cycloalkyl group; and X and Z are independently selectedfrom —Cl or —Br.
 23. The method of claim 22, wherein R⁸ and R⁹ areidentical but are not part of the same group and R⁸ and R⁹ aresubstituted or unsubstituted aryl groups.
 24. The method of claim 22,wherein the diacyl dihalide is phthaloyl dichloride.
 25. A method ofsynthesizing a diazaphosphacycle transition metal complex, comprising:(a) synthesizing the diazaphosphacycle according to the method of claim22; and (b) reacting the diazaphosphacycle with a starting transitionmetal complex to provide the diazaphosphacycle transition metal complex.